JPH0221572B2 - - Google Patents

Description

[Detailed description of the invention]

(1) Field of the Invention The present invention is useful in the field of photography. Main departure
The light shows a flat plate consisting of a dispersion medium and silver halide grains.
This invention relates to shaped grain silver halide emulsions. (2) Prior art A: Tabular silver halide grains A radiation-sensitive emulsion is used in silver halide photography.
However, such emulsions also contain a dispersion medium, usually gelatin.
and a radiation-sensitive halogen embedded in it.
Silver microcrystals (also known as particles)
It's flowing. Silver halide photographic emulsions contain various regular and
and irregular particle shapes have been observed. rules
particles are often cubic or octahedral.
Ru. Particle edges show roundness due to aging effect.
obtain. Also, use of strong ripening agents such as ammonia
In the presence of
It can be almost like a thick plate. This is an example
For example, Land U.S. Patent No. 3,894,871 and
and Zelikman and (Levi)
“Manufacturing and Coating of Photographic Emulsions”
Coating Photography
Focal Press, 1964,
Described on pp.221-223. rod and flat
Platy particles are often mixed in with other particle shapes.
It has been observed in various proportions. This is especially
The pAg (reciprocal of the logarithm of the silver ion concentration) of the emulsion is
For example, as seen in single-jet precipitation
Observed when sea urchin changes during the process of sediment formation.
Ru. Although tabular silver bromide grains have been extensively studied,
These particles are mostly macro-sized.
Therefore, it cannot be used in the field of photography.
Ivy. Here, tabular grains are each a grain.
substantially larger than any other single crystal plane in
Has two parallel or nearly parallel crystal planes
Refers to particles. Aspect ratio of tabular grains (immediately
The ratio of diameter to thickness is substantially 1:
Greater than 1. High aspect ratio tabular grain bromide
Silver emulsions are Cugnac and Chateau.
(Chateau) “Morphology of silver bromide crystals during physical ripening
Advances in Science (Evolution of the Morph)
Orgy of Silver Bromide Chestnut
Stars Due to Physical Life
) Science and Industry
Otography, Vol. 33, No. 2 (1962), pp. 121−
125 reported. Eastman from 1937 to the 1950s
Kodatsuku Co., Ltd. is Duplicated (registered trademark)
Geographic e-film products at no cost
It was sold under the name X-ray code 5133. this
The product is attached to opposite major sides of the film support.
with a sulfur-sensitized silver bromide emulsion as a coating film.
Ta. This emulsion is for exposure to X-rays and
Therefore, it was not spectral sensitized. Tabular grains are flat
It had an average aspect ratio of about 5-7:1. child
The tabular grains account for more than 50% of the projected area of the grain.
occupies more than 25% of the projected area.
It was dominated by tabular grains. How many times are these emulsions
Of the things that can be replicated several times, the most
Emulsions with high average aspect ratios have an average tabular
Grain diameter 2.5 micrometers, average tabular grain
Child thickness 0.36 micrometer and average aspect
A contrast ratio of 7:1 was shown. The emulsions of other reproductions are more
thicker, larger diameter tabular grains,
Its average aspect ratio was small. Tabular grain silver bromoiodide emulsions are used in the photographic industry.
Although known, high average aspect ratio
There are no known indications. tabular silver bromoiodide
The grains are manufactured by Duffin “Photographic Emulsion Chemistry”
Otographic Emulsion Chemistry
)” Focal Press, 1966, pp.66-72
and Trivelli and Smith.
(Smith) “Influences on the structure of the bromoiodide precipitation series”
The Effects of Silver Iodide” The Photographic Journal
Nall, Volume LXXX, July 1940, pp. 285-288.
explained. Trivelli and Smith Iodized
particle size and aspect ratio by introducing
We have observed a significant reduction in both. Gutov
(Gutoff) “Precipitate formation in silver halide photographic emulsions”
"Nucleation and growth rate in
Fuku Sciences and Engineers
Ring, Volume 14, No. 4, 1970, July-August,
pp. 248-257 describes single precipitation using a continuous precipitation device.
Odors of the type prepared by diet precipitation
The preparation of silver oxide and silver bromoiodide emulsions has been reported.
Ru. The main part of silver halide is in the form of tabular grains.
Existing emulsion preparation techniques are described in recent publications.
has been done. US Patent No. 4,063,951 {100}
Boundary defined by cubic faces and aspect
has a pitch ratio (based on edge length) of 1.5 to 7:1
It has been discovered that the formation of tabular crystalline silver halide
It is shown. The tabular grains of this are square and
The rectangular main plane exhibited the characteristics of a {100} crystal plane.
U.S. Pat. No. 4,067,739 describes the formation of seed crystals and
Stowald ripening increases the size of the seed crystals
and pBr (the inverse of the logarithm of the bromide ion concentration)
renucleation or Ostwal while controlling
Grain growth can be completed without dry ripening.
It is an octahedral crystal with mostly twin crystals.
The preparation of silver halide emulsions is described.
U.S. Patent No. 4150994, U.S. Patent No. 4184877 and U.S. Pat.
No. 418478, British Patent No. 1570581 and Doi
TS Patent Publication Nos. 2905655 and 2921077
Seed crystals with at least 90 mol% iodide
By using a flat twinned octahedral halo
has been taught to form silver germide grains.
Ru. Here, unless otherwise specified, halogenated
All percentages are for the corresponding emulsion, grain or
Based on the silver present in the grain region. For example, 90 mo
grains consisting of silver bromoiodide containing 1% iodide
contains 10 mol% iodide. The pull mentioned above
Some examples include increased covering power.
Emulsions with black and white and black and white are reported.
It can be useful as a camera film for both cameras.
explained. U.S. Patent No. 4,063,951
Physically, it is reported that the upper limit of the aspect ratio is 7:1.
However, the example has a very low
It only mentions a spectral ratio of 2:1.
First, the 7:1 aspect described in this specification
The ratio is considered unrealistic. repeat
Examples developed and micrographs published
If you look at it, the aspects seen in the other above-mentioned citations.
The ratio is less than 7:1. Japanese Patent Application Laid-open No. 142329 (Publication date: 1982)
No. 4150994 (November 6)
It is thought that similar teachings have been made in
It is not limited to the use of silver iodide seed grains. difference
Furthermore, this publication specifically states that less than 50 mol%
Formation of tabular silver chlorobromide grains containing chloride of
is mentioned. Examples of such emulsions are especially
Not shown. However, the information listed
Considering this, in the case of this publication, it is relatively low.
The percentage of tabular silver halide grains obtained is
and the aspect ratio of the resulting particles is
Not larger than that of U.S. Patent No. 4150994
That is clear. B Composite silver halide grains The advantages of independent silver halide grains are simply explained.
Achieved in one silver halide grain structure
It is said that multiple halides are combined in order to
The method is recognized in this technical field.
By the way, although it is not acknowledged,
has also been used in this field since early on.
Ru. German Patent No. 12 August 1930
No. 505012 has a green color tone after development.
teaches forming silver halide emulsions.
Ru. This means that potassium iodide and sodium chloride
under conditions consisting of sequentially introducing
achieved by precipitating silver halide.
can be achieved. manufactured by this method
When the emulsion was tested, very small silver iodide grains were found.
children (with an average diameter of virtually 0.1 micrometers)
It can be seen that the formation of Independent
Silver chloride grains are formed and also electron micrograph
Therefore, silver chloride grains also undergo epitaxial growth.
Precipitated on silver iodide grains
I understand. As the silver iodide grain size increases
and the resulting desired green tone to brown.
A color change to the color tone occurs. German patent no.
What essentially overlaps with the teaching content of No. 505012
Photographer Industry
(Photographische Industrie), “Green-and-brown
Color developing emulsion (Green-and-Brown-
Developing Emulsions), Volume 34,
pp.764.766 and 872, July 8 and August 1938
Included in 5 daily newspapers. British Patent No. 1027146 describes complex halogenated
Techniques for forming silver particles are disclosed. Halo
Forming a core or core particle of silver genide, and then
one or more silver halide emulsion layers adjacent to
Cover. Such composite silver halide grains are
Contains silver chloride, silver bromide, silver iodide or mixtures thereof
do. For example, a layer of silver chloride on a core of silver bromide or
Coating a layer of a mixture of silver bromide and silver iodide
You can, otherwise, put it on the core of silver chloride
Including a layer of deposited silver bromide
can. British Patent No. 1027146 is based on silver bromide.
When silver chloride is deposited, the resistance to silver bromide is
The spectral response and developability characteristics of silver chloride are obtained.
It teaches that it can be done. In US Patent No. 3505068, UK Patent No.
Using the teaching content of No. 1027146, relatively low
High sensitivity to achieve deep dye image contrast
Low sensitivity milk to be used in combination with emulsion layer
The agent layer is being prepared. Used in low-speed emulsion layers
The silver halide grains used are silver iodide or halide grains.
Core consisting of silver iodide, and containing iodide
For example, from silver bromide, silver chloride or silver chlorobromide
It has a shell. US Patent No. 4094684
The name is in the shape of a truncated bipyramid (Ururu).
Silver iodide with a hexagonal crystal structure (Tsunite type)
Silver chloride is deposited on top by epitaxial growth.
Discloses the details. According to this patent
For example, through the use of composite grains, silver iodide
The light absorption properties of silver chloride and the developing performance properties of silver chloride
Both can be achieved together.
U.S. Pat. No. 4,142,900 is essentially the above-mentioned U.S. patent.
Although it is similar to
Conventional halide convergence after long deposition
Silver chloride is converted to silver bromide by the Yon method.
They differ in that they are UK patent application no.
No. 2053499A is essentially U.S. Pat. No. 4,142,900.
Although similar, this UK application
Epitaxial growth of silver bromide on silver iodide
is carried out directly. European patent application no.
Issue 0019917 (release date: December 10, 1980) is 10
Silver halide containing less than mol% iodide
Silver halide containing 15-40 mol% iodide
Deposited by epitaxial growth on particles
Discloses that. U.S. Patent No. 3,804,629 physically matures
The washed emulsion is then subjected to chemical ripening.
Add silver chloride emulsion in advance or physically
Aged and washed silver halide emulsion
by precipitating silver chloride on top.
against the harmful effects of dust, especially metal dust.
Can improve the stability of the silver emulsion layer
It is disclosed that This US patent
The silver chloride thus deposited is
Small protrusions on pre-formed silver bromide grains
It is also true that it will form a hillock.
It has been disclosed. Berry and Skillman
(Skillman), “Surface on AgBr microcrystals
"Structures and Epitaxial Growth", Journal
of Applied Physics, Volume 35, No.
7, July 1964, pp.2165-2169,
Disclose the growth of silver chloride on silver chloride.
There is. The octahedrons of AgBr are
Forms erect growths and is more than a cube
Has great reactivity. the cube carries out the reaction
However, mainly the corners,
And this is the edge part. twin plate
For crystals with random
It forms growths that are distributed in
The growth of the part near the azalea is slightly more advanced.
It has been observed that Add more
After the emulsion coating is bent, it forms a linear shape.
may form growths arranged in
This is also due to the effect of the slip band.
It shows. C Sensitivity (speed), graininess and sensitization During imagewise exposure, the entire grain can be selectively developed.
A very small amount of radiation is applied to the center of the latent image where it is to be smoothed.
can be formed through the absorption of radiation, or
It is also unusually superior to many alternative imaging methods.
Gives silver halide photography superior sensitivity capability.
Whether or not it is possible to do so depends on this latent image.
Depends on cardiogenic potential. Various chemical sensitizations, e.g. noble metals (e.g.
gold), intermediate chalcogens (e.g. sulfur and/or
selenium), and reduction sensitization was developed.
In addition, these sensitizations can be used alone or in combination.
In addition, it is possible to improve the sensitivity of silver halide emulsions.
can be done. Chemical sensitization exceeds the best level
As a result, fog (minimum density) increases rapidly and
As a result of image discrimination power (maximum density minus maximum
small concentrations) are rapidly lost, and therefore the sensitivity is
The target increases slightly. Optimal chemical sensitization is specific
sensitivity to photo usage, image discrimination ability and
The best balance is between small concentrations. Usually, the sensitivity of silver halide emulsions depends on chemical sensitization.
Therefore, the spectral region of their inherent sensitivity cannot be ignored.
It's just a matter of going as far as you can. silver halide milk
The sensitivity of the agent is spectral as represented by methine dyes.
By using sensitizers, the entire visible spectrum can be
can be increased over time. Concentration of spectral sensitizer
As the sensitivity increases to an optimum value, the sensitivity of the emulsion becomes
increases beyond the sensitivity range, and generally its
(Mess, theory)
of the photography process,
(See Cumilan, 1942, pp. 1067-1069). Silver halide grains commonly found in photographic elements
Within the range of
The maximum sensitivity increases directly with increasing particle size.
increases linearly. required to make the particles developable.
The number of absorbed quanta required is essentially the same as the particle size.
Although it is technically unrelated, a certain number of particles are
The concentrations shown are directly related to their particle size.
Ru. If the purpose is to obtain a maximum density of 2.
mule, for example, average diameter 0.2 micrometers
0.4 micrometer particles compared to those
It is necessary to use smaller amounts of Few particles
The fewer particles there are, the more the particles can be developed.
The required radiation dose is smaller. Unfortunately, larger particles
The concentration is increased at fewer locations, so
For this purpose, point-to-point concentration fluctuations
becomes larger. Observer of concentration fluctuation between two points
This perception is called "graininess." between two points
An objective measurement of concentration variation is called “granularity”.
Ru. Quantitative measurement of granularity can be done in various forms.
However, granularity is most commonly measured using RMS (routine
(average mean square) granularity. RMS
The granularity is the observed micro-aperture (e.g. 24-48 micro-pores)
defined as the standard deviation of the concentration in chromium
be done. Maximum allowed granularity for a particular emulsion layer
(Also commonly called soko, but halogenated
(not to be confused with silver particles) is determined
and the maximum sensitivity that can be achieved for that emulsion.
Validly limited. The real improvement in silver halide emulsion sensitivity is due to granularity
Increases sensitivity without increasing sensitivity.
Reduces granularity without reducing and also increases sensitivity
and granularity at the same time.
Such sensitivity improvements are generally and easily
Improving the sensitivity-granularity relationship of emulsions in the true field
It is called. The graph shown in Figure 1 shows that although the composition is the same,
Five silver halide emulsions with different grain sizes
Same for each of 1, 2, 3, 4 and 5.
After applying various sensitization treatments and applying the same coating film,
Sensitivity − Grain for those subjected to the same processing
This is a plot of the state relationship. individual breasts
agents differ in maximum sensitivity and granularity
However, as shown by the sensitivity-granularity line A, the difference between emulsions
A predictable linear relationship exists between them. along line A
All emulsions present have the same sensitivity-granularity
Show relationships. Emulsions that show real improvement in sensitivity
exists above the sensitivity-granularity line A. example
For example, an emulsion existing on the common sensitivity-granularity line B
Emulsions 6 and 7 have higher sensitivity than any of emulsions 1 to 5.
Excellent in terms of granularity. Emulsion 6 is an emulsion
It has higher sensitivity than 1, but the granularity is not high.
stomach. Emulsion 6 shows the same sensitivity as emulsion 2, but with grain
The condition is quite low. Emulsion 7 has a higher feel than emulsion 2
However, the granularity is lower than that of Emulsion 3. Emulsion 3
Sensitivity is lower than Emulsion 7. Sensitivity-below granularity line A
Emulsion 8 located on the side is the lowest in Figure 1.
The sensitivity-granularity relationship is shown. Emulsion 8 is the above emulsion.
Among them, it shows the highest photographic sensitivity;
It only increases non-proportionally with granularity. In the field of photographic technology, the relationship between sensitivity and granularity is
Quantify sensitivity-granularity measurements because
And great efforts have been made to generalize it.
Ta. For example, a single particle such as silver halide grain size
Sensitivity-granularity of a series of emulsions differing in one property
Comparing relationships accurately is usually a simple matter.
Ru. Sensitivity-grain of photographic products showing similar characteristic curves
State relationships are often compared. However,
Invariant quantitative sensitivity of photographic elements - granularity
Comparison techniques have not been established. That is, other
When comparing the sensitivity and granularity when the photographic characteristics of
This is because dramatically more complex judgments are required.
In addition, photographic elements that form silver images (e.g. black and white
Sensitivity-granularity relationship of photographic elements) and formation of dye images
photographic elements (e.g. color and chromogenic photographs)
For comparison with the sensitivity-granularity relationship of
There are many factors to consider in addition to silver grain sensitivity.
included. This is because it produces concentration and
The properties and origins of materials that contribute to granularity
This is because they are very different. silver and dye images
For more information on granularity measurements in formation,
“Understanding Granularity and Granularity”
Graininess and Granularity), published by Kodatsuk.
Commemoration No. F-20, revised 11-79 (Eastman Co.
Datsuku Corporation, Rochiester, New York 14650
(Publisher); Zwick, “Influence on Granularity”
Quantitative study of the factors that influence
Studies of Factors Affecting
Granularity)”, Fotographik Saie
Science and Engineering, Volume 9, No.
3, May-June, 1965; Ericson
and Marchant, “Monodispersion
RMS granularity of true emulsions, Photographic
Science and Engineering, 16
Volume, No. 4, July-August, 1972, pp.253-257;
and Trabka, “On Pigment Clouds”
"Random Sphere Model", Photographic Service
Science and Engineering, vol. 21,
See No. 4, July-August, 1977, pp.183-192.
I want to be Outstanding silver image formation (black and white) sensitivity-granularity characteristics
The silver bromoiodide emulsion with
explained in the specification. In this specification, iodine
Silver preferably contains 1 to 10 mol% of halide
Gelatin-silver bromoiodide emulsions are disclosed.
Ru. Emulsions are sensitized with sulfur, selenium or tellurium
Sensitized. This emulsion has a silver coverage on the support.
is a square foot (0.929m ² ) 300-1000mg per
Apply it until the intensity is
Exposure using a Kehl sensitometer and temperature at 20 °C (68
〓) Kodatsu developer DK-50 (N-
Methyl rp-aminophenol sulfate high
When processed for 5 minutes using droquinone developer)
has a log sensitivity of 280 to 400, and this log sensitivity
After subtracting the granularity value from the degree, the remainder is 180 to 220.
be. Using gold in combination with sulfur-based sensitizers
and during the formation of the halogenated precipitate.
Thiocyanate may also be present in the
If desired, you can also check at any time before cleaning.
Oceanate may be added to the silver halide.
Thiocyanate during silver halide precipitation formation
U.S. Pat. No. 2,221,805,
Described in the same No. 2222264 and the same No. 2642361
ing. Milk as described in U.S. Patent No. 3,320,069
The agent also has remarkable sensitivity in color photography - graininess.
granularity characteristics (especially for dye image granularity)
Although quantitative figures are not given). U.S. Patent No. 3656962, U.S. Patent No. 3852066 and U.S. Pat.
In No. 3852067, inorganic crystalline materials are treated with halogens.
It is taught that it is mixed into silver oxide emulsions.
According to these, Halo
Physically and densely bonding silver germide grains and inorganic crystals
By combining the silver halide emulsion with light
You can change the sensitivity to US Patent No.
No. 3140179 is an optically sensitized emulsion.
An optically sensitized emulsion consisting primarily of silver chloride
Forming a visible image inside during exposure and development
Coating an emulsion with sufficiently low sensitivity
The sensitivity and sensitivity of the optically sensitized emulsion can be increased by
It is possible to further increase the contrast.
It teaches that. U.S. Patent No. 3152907
is a low-speed silver chloride emulsion and an optically sensitized salt.
By blending with silver oxide or silver bromoiodide emulsion,
that you can get similar benefits by using
teaching. UK Patent Application No. 2038792A is based on {100} crystals.
is surrounded by surfaces and therefore those surfaces are boundaries.
The cubic particles that form the field are
teaches selective sensitization in the
There is. Such sensitization begins with tetradecahedral silver bromide grains.
This can be achieved by forming
Ru. These particles are surrounded by {100} major crystal planes.
It is an ordinary cubic particle that is
If there is a defect in the corner of the cube,
in each case adjacent to that absent corner.
{111} crystal plane remains. Then silver chloride
selectively deposited on these {111} crystal faces.
let The obtained grains are separated into silver halide corner parts.
can be selectively chemically sensitized. It takes
Sensitivity can be improved through localization of sensitization.
Wear. Regarding composite crystals, if those crystals
responds to sensitization when silver chloride
However, if those crystals were silver bromide,
for developing, fixing and cleaning during photographic processing.
If you respond to this, it will be disclosed. british patent
In application No. 2038792A, the {111} crystal plane
How to selectively sensitize particles with
There was no instruction as to whether it could be adapted.
If so, it has not been proposed. Sea bass and fish
``Activities for chemical sensitization of monodisperse AgBr emulsions''
The Active Sites for Chemical
Sensitization of Monodisperse AgBr
Emulsions), 1937, SPSE Tokyo Symposium
is also considered to have made similar disclosures. However
In this case, a superstructure is placed on the corner of the silver bromide cube.
Fine-grained silver chloride is subjected to Ostwald ripening. During chemical sensitization, the sensitized area of the silver halide emulsion
Usually formed on the particle surface and also in their parts.
The distribution of positions is more or less random. grain
It is slightly more advantageous to perform a specific arrangement on the child.
Even in some cases, e.g.
Place the sensitized site at or near the
Even in cases where the
Their sensitized sites are still randomly separated from each other.
They will exist scattered. Halogen latent image area
A large number of photoelectrons are required to form on silver oxide grains.
(photogenerated electron)
Because it is necessary, it is obvious that they should be closely adjacent.
The sensitizing sites are halogenated where those sites are present.
Competing for photoelectrons in the silver particle area
and therefore such competition
to achieve otherwise in the absence of
silver halide grains to the maximum level that can be
Unable to increase child's sensitivity. (3) Disclosure of the invention An object of the present invention is to provide a dispersion medium and silver halide grains.
Tabular grains with enhanced sensitivity consisting of
The object of the present invention is to provide a child silver halide emulsion. This purpose, according to the invention, is achieved by using a dispersion medium and a halogen.
Tabular grain silver halide milk consisting of silver halide grains
an agent that covers at least the total projected area of the silver halide grains;
50% are less than 0.5 micrometers thick, direct
A minimum diameter of 0.6 micrometers and an average as
Tabular halogenation with a spectral ratio greater than 8:1
occupied by silver grains, and parallel to each other where the tabular silver halide grains face each other.
the silver halide having {111} main crystal faces and forming the tabular grains;
Silver salts having different compositions are arranged at the edges of the tabular grains.
Tabular grain halogen characterized by
This can be achieved by using a silver oxide emulsion. Furthermore, according to the present invention, the dispersion medium and the halogenated
A tabular grain silver halide emulsion consisting of silver grains.
At least the total projected area of the silver halide grains is
50% are less than 0.5 micrometers thick, direct
A minimum diameter of 0.6 micrometers and an average as
Tabular halogenation with a spectral ratio greater than 8:1
occupied by silver grains, and parallel to each other where the tabular silver halide grains face each other.
{111} main crystal faces, and the silver salt containing the sensitivity improver is
A flat halo characterized by being placed on the edge
Silver germide emulsions are also provided. Furthermore, according to the present invention, the dispersion medium and bromoiodination
A tabular silver halide emulsion consisting of silver grains.
and at least 50% of the total projected area of the silver bromoiodide grains.
%, thickness less than 0.5 micrometer, diameter
Minimum 0.6 micrometer and average aspect
tabular silver bromoiodide grains with a to ratio of greater than 8:1.
The tabular silver bromoiodide grains face parallel {111}
The tabular silver bromoiodide grain has a main crystal plane, and the tabular silver bromoiodide grain has a main crystal plane in its central region.
less than 5 mol% of iodide in the central region;
Maximum in an annular area that surrounds and extends laterally.
contains as low as 8 mol% iodide, and has a composition similar to that of the silver bromoiodide forming the central region.
different silver salts in the central region of the tabular grains.
The portions of the opposing parallel principal crystal planes formed by
are placed above the area and the placement is restricted to that area.
A tabular silver halide milk characterized by
Agents are also provided. D. Tabular grain emulsions and their preparation The tabular grains of the present invention can be prepared by
surrounded by nearly parallel {111} principal crystal planes.
Also, these particles are generally hexagonal
It has a system or triangular shape. The present invention
The main grains facing each other in the tabular silver halide grains are
The crystal planes are parallel. The term "parallel" means that
When used in this specification, 10000 times
appear parallel on direct or indirect visual inspection.
It is intended to encompass multiple surfaces.
The term "high aspect ratio" refers to it as a feature of the present invention.
0.5 micro when applied to silver halide emulsions
Thickness less than meter and minimum 0.6 micrometer
Silver halide grains with a diameter of
Spectral ratio greater than 8:1 and halogen
occupy at least 50% of the total projected area of the silver
We hereby state that this is necessary.
can be defined as High aspect ratio tabular grain halo according to the present invention
The preferred silver generide emulsion is 0.3 micro
less than 0.2 micrometers (preferably 0.2 micrometers)
thickness of at least 0.6 micrometers) and at least 0.6 micrometers thick.
silver halide grains with a diameter of
at least 12:1, preferably at least 20:1
It is an emulsion having an average aspect ratio.
These halves meet the thickness and diameter criteria listed above.
In a preferred form of the invention, silver halide grains are
is at least the total projected area of silver halide grains.
also account for 70%, and preferably at least 90%.
have of tabular grains occupying a given percentage of the projected area
The thinner the emulsion, the higher the average aspect ratio of the emulsion.
It is understood that the ratio will be higher. usually flat
The average thickness of the particles is at least 0.03 micrometers.
torr, preferably at least 0.05 micrometers.
(for example, 0.01 micrometres)
Thinner tabular grains such as
Although it is available). satisfy a specific purpose
It is said that the thickness of tabular grains can be increased to
It is recognized that For example, image transfer film
For units, up to 0.5 micrometers
Tabular grains having an average thickness are useful.
For average particle thickness up to 0.5 micrometers
This will also be explained below in the record of blue light.
I will clarify. However, if the diameter of the particles is increased too much,
In order to achieve a high aspect ratio without
The tabular grains of the emulsion according to the invention are 0.3 microns.
It will have an average thickness of less than a meter. child
The thickness of tabular grains as reported here is
It is based on the thickness of the host particle, and
As described in detail below, silver salt
Thickness due to deposition by pitaxial growth
does not include an increase in The above-mentioned grains of the silver halide emulsion according to the present invention
Characteristics can be easily verified by methods well known to those skilled in the art.
can be done. As used in this specification
The term "aspect ratio" refers to the ratio of particle thickness to
Shows the ratio of diameters. The “diameter” of a particle is
Observe the material using a microscope (or electron microscope) photo.
of a circle with an area equal to the projected area of the particle
It refers to the diameter. Shaded emulsion sample
Thickness of each tabular grain from electron micrograph
Can measure thickness and diameter, and thickness
Less than 0.5 micrometers (preferably 0.3 micrometers)
chroma) and at least 0.6 mm in diameter
Identify tabular grains with ichromators
be able to. The diameter that can be measured in this way and
From the thickness, the aptitude of each such tabular grain is determined.
The spectral ratio can be calculated, and the thickness
0.5 micrometers (0.3 micrometers)
) and at least 0.6 micrometers in diameter.
All grains in the sample that meet the criteria of
Average the aspect ratios of the children and calculate their average aspect ratio.
Spectral ratio can be obtained. From this
As is clear, the average aspect ratio is
It is the average aspect ratio of individual tabular grains.
Ru. In practice, typically 0.5 micrometers thick
(0.3 micrometers) and diameter
Tabular grains with at least 0.6 micrometers
Find the average thickness and average diameter of the child, and
The average aspect is calculated by calculating the ratio of the two average values.
It is easy to find the ratio. average aspect ratio
The average value of the individual aspect ratios is used to determine
Also use the average value of thickness and diameter
However, it is still within the acceptable range for possible particle measurements.
Then, the average aspect ratio obtained is effectively
There is no difference. Halogen that meets thickness and diameter standards
Sum the projected area of the silver oxide grains, and also
The projected area of the remaining silver halide grains in the photograph is
Sum them separately, and then calculate the sum of these two
Tabular grains satisfying the thickness and diameter criteria
percentage of the total projected area of silver halide grains
rate can be calculated. In the above determination, 0.5 micrometer
less than (preferably less than 0.3 micrometer)
The standard tabular grain thickness of
Very thin tabular grains with poor photographic properties
It was selected to distinguish it from the tabular grains. mark
Choose 0.6 micrometer as quasiparticle diameter
is. This is because the smaller the diameter, the smaller the microscopic image.
True, tabular grains and non-tabular grains are not necessarily distinguished.
This is because they cannot be separated. The term “projection area”
Extended Area) is widely used in this industry.
The term “projection area”
area or project area
A) is used in the same sense. this term
For example, James and Higgi
Higgins, “Fundamentals of Photographic Theory”
(Fundamentals of Photographic Theory)”
Morgan & Morgan New York.
Please refer to p.15. High aspect ratio tabular grain silver bromoiodide emulsions are
It can be prepared by precipitation method as described below.
Possible: Regular halogen with effective stirring mechanism
A dispersion medium is placed in a reaction vessel for silver oxide precipitation. General
Usually, the dispersion medium is added to the reaction vessel in the first step.
amount present in the silver bromoiodide emulsion at the final stage of grain precipitation.
at least about 10% by weight of the amount of dispersion medium present, preferably
Preferably 20 to 80% by weight (total weight of dispersion medium)
). Belgian Patent No. 866645 (Full)
(corresponding to Lance Patent No. 2471620)
As shown in the figure, the dispersion medium is limited in the silver bromoiodide grain precipitation process.
Can be removed from the reaction vessel by filtration.
Since the amount of water present in the reaction vessel can be
The volume of dispersion medium is increased in the reaction vessel during the final particle precipitation stage.
equal to or greater than the amount of silver bromoiodide emulsion present
It can even be done. first in the reaction vessel
The dispersion medium to be added is preferably water or peptizer.
This is an aqueous dispersion of the agent, and this dispersion medium can be used as needed.
and other ingredients, e.g.
silver halide ripening agent and/or after
Contains metal dopants as detailed below. Remove the deflocculant
If present at the beginning, the final stage of silver bromoiodide precipitation
at least 10% of the total amount of deflocculant present in the floor;
Particularly preferably it at a concentration of at least 20%
It is preferable to use silver and halogenated
Add additional dispersion medium to the reaction vessel along with the salt
However, this can also be introduced from another jet.
Wear. Generally, especially increasing the proportion of peptizer
After completing the introduction of halide salts for
Adjust the proportion of dispersion medium. A small fraction of bromide salt used to form silver bromoiodide grains
In most cases, less than 10% by weight is initially present in the reaction vessel.
minutes at the beginning of silver bromoiodide precipitation.
Adjust the bromide ion concentration in the dispersion medium. Also,
The dispersion medium in the reaction vessel initially contains iodide ions.
No. This is because silver and bromide salts are added at the same time.
If iodide ions are present before the
This is because non-tabular grains are likely to be produced. anti
The term ``substantially'' used herein with respect to the contents of the reaction vessel.
"free of iodide ions" means "free of bromide ions"
Iodide ion has a separate silver iodide phase compared to on
present in insufficient amounts to form a precipitate as
means not present. Before introducing silver salt
The iodide concentration in the reaction vessel depends on the amount of halogen present.
Less than 0.5 mol% of the total concentration of genide ions
It is desirable to maintain the The pBr of the dispersion medium is
If the initial height is too high, the tabular silver bromoiodide grains formed will be
relatively thick and therefore has a low aspect ratio.
Become something. The pBr in the reaction vessel was initially set to 1.6 or
should be kept below that, preferably below 1.5.
I can do it. On the other hand, if pBr is too low, a non-flat plate
Silver bromoiodide grains are likely to form. Therefore, the reaction volume
The pBr of the device should be 0.6 or higher, preferably 1.1 or higher.
can be maintained on. used here
pBr is defined as the negative logarithm of bromide ion concentration
be done. PH and pAg also represent hydrogen and silver, respectively.
Similarly defined for ion concentration. During precipitation, silver bromoiodide grains are precipitated.
silver, bromide and iodide according to well-known techniques for production
Add the salt to the reaction vessel. Usually bromide and iodine
Simultaneously with the introduction of compound salts, such as silver nitrate,
An aqueous solution of soluble silver salt is introduced into the reaction vessel. Ma
In addition, bromide and iodide salts are usually one type or another.
Soluble ammonium, alkali
metals (e.g. sodium or potassium) or
or alkaline earth metals (e.g. magnesium
or calcium) in an aqueous solution of a halide salt.
It is introduced as an aqueous salt solution. Less silver salt
Both were initially introduced into the reaction vessel separately from the iodide salt.
do. Iodide and bromide salts are separated in the reaction vessel.
It can be added to or introduced as a mixture.
stomach. Introducing a silver salt into the reaction vessel can reduce particle formation.
The nucleation phase begins. Silver, bromide and iodide
Continuing to introduce salts leads to precipitation of silver bromide and silver iodide.
A population of particle nuclei is formed that serves as a site for sediment formation.
be done. Silver bromide and iodide on the grain nuclei present
Silver precipitation constitutes the growth stage of grain formation.
Ru. Ata of tabular grains formed in accordance with the present invention
The spectral ratio is the nucleation stage and the growth stage.
Less affected by chemical and bromide concentrations
stomach. Therefore, silver, bromide and iodide salts at the same time
The permissible range of pBr at the introduction stage is determined by the growth stage.
between floors 0.6 or more, preferably in the range of about 0.6 to 2.2
range, more preferably in the range of about 0.8 to about 1.6.
can do. Of course, silver and halogen
pBr in the reaction vessel during the process of introducing compound salts.
Keep it within the above-mentioned period before introducing silver salt.
It is possible and in fact possible to do so.
It's advantageous. This means that highly polydispersed milk
Silver, bromide and iodide as when preparing agents
During the introduction of salt, particle nucleation is substantially
This is particularly advantageous when sustained at a certain speed.
pBr value of 2.2 or more at tabular grain growth stage
The thickness of the resulting particles increases as
However, the average aspect ratio is still larger than 8:1.
is acceptable in many cases because it yields particles that
be able to. Introducing silver, bromide and iodide salts as aqueous solutions
silver, bromide and iodide salts instead of
Form of fine silver halide particles suspended in dispersion medium
can be introduced at an early or growing stage in the
can. The particle size is determined by the amount of particles introduced into the reaction vessel.
If there is a larger particle nucleus when
If the particles are
It's like a Waldo ripening. useful max
Particle size depends on specific conditions within the reaction vessel, e.g.
depending on the temperature and the presence of solubilizers and ripening agents.
will. Silver bromide, silver iodide and/or odor
Silver iodide grains can be introduced. Bromide and
and (or) iodides precipitate in preference to chlorides.
Therefore, silver chlorobromide and silver chlorobromoiodide grains are used.
You can also do that. Silver halide grains are extremely fine.
fine, e.g. 0.1 micrometer in average diameter
It is preferable that it is less than Provided that the above pBr condition is satisfied.
The concentration of silver, bromide and iodide salts introduced and
Speed is a conventionally used advantage.
stomach. 0.1 silver and halide salts per liter
Although preferably introduced at a concentration of ~5 molar,
A wider concentration range than conventionally used, e.g.
For example, from 0.01 mole per liter to saturation.
It is possible to adopt Particularly preferred method of forming a precipitate
silver and halide salts during operations.
Precipitate formation by increasing the introduction rate
It's like trying to save time. silver and ha
The rate of introduction of the halide salt depends on the dispersion medium and silver and
and increasing the rate of introduction of halide salts.
Silver and silver in the dispersion medium introduced by or
by increasing the concentration of salts and halide salts.
can be increased. silver and halogen
It is advantageous to increase the rate of introduction of the chloride salt.
However, U.S. Patent No. 3650757 and U.S. Patent No. 3672900
No. 4242445, German Patent Application Publication No. 4242445
Report No. 2107118, European Patent Application No.
No. 80102242, and Wey “Gelatin
Growth mechanism of AgBr crystals in solution
(Growth Mechanism of AgBr Crystals in
Gelatin Solution) Photographic Science
and Engineering.Vol.21.No.1, January 1977-
New grains as taught in February, p.14 et seq.
Introducing speed below the limit value at which generation of child nuclei is likely to occur
(i.e. to avoid re-nucleation)
) is particularly advantageous. Fluctuations of less than approximately 30%
An emulsion can be prepared that has a coefficient of
(The coefficient of variation used here is the standard particle diameter
Means 100 times the deviation divided by the average particle diameter
do. ) Deliberately renucleated during the growth phase of the precipitate
Of course, by causing the generation
to prepare polydisperse emulsions with higher coefficients of variation.
can be manufactured. The iodide concentration in the silver bromoiodide emulsion according to the present invention is
Controlled by the introduction of iodide salts
Can be done. Any commonly used iodide concentration can be used.
It can also be used. even a very small amount of iodide
amount, even at low values, e.g. 0.05 mol%
It is recognized as useful in this technical field. Book
The emulsions of the invention in their preferred form are
and contains at least 0.1 mol% iodide. grain
up to the solubility limit in silver bromide at the particle formation temperature.
Introducing silver iodide into tabular silver bromoiodide grains
Can be done. Therefore, at the precipitation temperature of 90℃
Approximately 40 mol% of silver iodide is contained in tabular silver bromoiodide grains.
It can be present at a concentration of . actual
Then, the precipitation temperature is set to about room temperature, for example about 30℃.
It can be reduced to Generally, precipitation
It is desirable to carry out the production at a temperature range of 40-80°C.
stomach. For most photographic applications, the maximum iodide concentration
It is desirable to limit the amount to about 20 mol%. best
The iodide concentration of is up to about 15 mol%. Iodide introduced into the reaction vessel during the precipitation process
The relative proportions of bromide and bromide salts are kept constant.
With this, there is substantially uniform iodine in the tabular silver iodide grains.
It is also possible to form a compound profile (distribution).
You can also change the above relative proportions.
You can also create cool photo effects. high ass
In the annular region of a tabular grain silver bromoiodide emulsion,
The proportion of iodide in the center of the tabular grains
When increased compared to the area, certain photographic features
Provides sexual benefits. center of tabular grain
The iodide concentration in the region ranges from 0 to 5 mol%
It can also be changed by a ring surrounding the lateral
The iodide concentration in the
Iodination in silver bromide from 1 mol% higher value for both
Up to the solubility limit of silver, preferably about 20 mol%
Optimally, it can be varied within a range of up to about 15 mol%.
I can do it. Tabular silver bromoiodide grains according to the present invention
is substantially uniform or gradually changing
iodide concentration profile
It is also possible to control the iodide concentration gradient as desired.
inside the tabular silver bromoiodide grains.
increase the concentration of iodide in the particles or
Iodide concentration at or near the outer surface of
can be made higher. Preparing a neutral or non-ammoniac emulsion as described above
See how to remove high aspect ratio tabular grain odors
Although we have explained the method for preparing silver iodide emulsions,
Emulsions and their utilities related to light
Not limited by specific preparation methods
do not have. According to another method, silver halide seeds
The child is initially present in the reaction vessel. reaction vessel
The silver iodide concentration inside is 0.05 mol per liter
In addition, the amount of water in the reaction vessel was reduced to less than
The maximum size of silver iodide grains initially present is
reduced to less than 0.05 micrometers
Ru. Iodide-free high aspect ratio tabular grains
Silver bromide emulsions are prepared using iodide using the method detailed above.
Prepared by a method modified so that it does not contain
be able to. High aspect ratio tabular grain bromide
Silver emulsions are also used in Kunatsuk and Schier, cited earlier.
It can also be prepared by a method based on
Ru. High aspect ratio tabular grains without iodide
Further methods for preparing silver bromide emulsions are described below.
This will be explained in examples. High aspect ratio that can be used to practice the present invention
The versatility of tabular grain silver halide emulsions
In addition, both silver bromide and silver iodide are
Regarding the preparation method of tabular silver chloride grains that do not contain
I will explain. In this preparation, a dispersion medium is included.
chloride in the presence of ammonia in a reaction vessel containing
Double-jet precipitation that introduces both silver salts at the same time
Use the lees method. During the introduction of the chloride salt, the dispersion medium
Maintain pAg in the range of 6.5-10, and pH
Keep it in the range of 8-10. to a higher temperature
When ammonia is present in the
There is a tendency to generate. Therefore, high aspect ratio
Precipitate formation when preparing tabular grain silver chloride emulsions
The temperature limit is 60℃. {111} has opposing crystal planes in the crystal plane, and
In one preferred form, one of the major surfaces
A small number parallel to the <211> crystal vector in the plane of
At least 50 with at least one edge
Preparing tabular grains containing mol% chloride
It is also possible. Such tabular grain milk
The agent is a crystal habit-changing amount of aminoazaindene and thiol.
Aqueous silver salt in the presence of an ether bond-containing peptizer
and an aqueous solution of a chloride-containing halide salt.
It can be prepared by reacting. at least the annular region of the particle and preferably the annular region of the particle
Contains chloride and bromide throughout the product
Tabular grain emulsions consisting of silver halide grains are also
can be prepared. Containing silver chloride and silver bromide
The tabular grain region contains silver, chloride, bromide, etc.
Add each iodide salt to the reaction vessel as needed.
moles of chloride and bromide ions in the process of introducing
Maintain the ratio between 1.6:1 and about 260:1 and
The total concentration of halide ions in the reaction vessel
By maintaining the degree within the specified range of 0.10 to 0.90.
is formed. Against bromide in tabular grains
The molar ratio of chloride is in the range of 1:99 to 2:3.
It can be changed. High aspect ratios useful in practicing the invention
Tabular grain emulsions have extremely high average aspect ratios
can have. Average particle diameter (particle size)
By increasing the average asperity of tabular grains,
can increase the effective ratio. In this way
Benefits regarding sharpness can be obtained. However
However, the maximum average particle diameter is generally
Depending on the granularity requirements imposed for the actual application.
is restricted. Average aspect of tabular grains
The ratio may also or alternatively be the average grain thickness.
It can be increased by lowering the value.
When maintaining a constant silver coverage, flat plate
Improved granularity by reducing particle thickness
can do. Such granularity improvement is
achieved as a direct function of spectral ratio increase
be able to. Therefore, the flat plate according to the present invention
The maximum average aspect ratio of a shaped grain emulsion is
Maximum average particle diameter acceptable for chamber applications
functions, and things that can be manufactured.
as a function of the minimum tabular grain thickness achievable at
be. The precipitation method used and the tabular grain halo
Maximum average aspect depending on genide composition
It turns out that the ratio changes. Photographic
For tabular grains with average grain diameters useful for
the highest average aspect observed
Ostwald ratio of silver bromide grains is 500:1.
This can be achieved by the ripening method, or
100:1, 200:1 or even higher
A high aspect ratio is obtained by double jet precipitation method.
It was achievable. iodide is present
, the maximum average aspect ratio that can be realized is
be lowered. However, the average asper
100:1 or 200:1.
or even larger than that.
Preparation of silver bromoiodide tabular grain emulsions is also possible.
It is. Optionally containing bromide and/or iodide
silver chloride tabular grains with 50:1 or
Furthermore, the average asperity with a size such as 100:1
It is possible to achieve a high efficiency ratio. modifying compound
It can be made to exist during the precipitation process of tabular grains.
Wear. Such compounds are initially introduced into the reaction vessel.
may be made to exist in
and add one or more types of salt.
It can also be added to. US Patent No. 1195432
No. 1951933, No. 2448060, No. 2448060, No.
No. 2628167, No. 2950972, No. 3488709,
Same No. 3737313, Same No. 3772031 and Same No.
Issue 4269927 and Research Disclosure
Vol.134, June 1975, Item 13452
For example, copper, thallium, lead, bismuth
gas, cadmium, zinc, intermediate chalcogen (immediately
sulfur, selenium and tellurium), gold, and
Halo modified compounds such as compounds of noble metals
It can be present in the process of silver generide precipitate formation.
Ru. Research Disclosure and its predecessors (old editions)
The Product Licensing Index, which is
PO9−1EF, Hampshire Harvard, Ho
Industrial Opochi located in Muueru
Unity's Limited (Industrial)
Opportunities Ltd.). flat plate
Particles are described in Moiser et al., Journal of
Photographic Science, Vol.25, 1977,
Precipitate formation process as described on pp.19-27
Internal reduction sensitization can be carried out. Each silver salt and halide salt is
Patent No. 3821002 and Patent No. 3031304, and Ku
Claes etc., Photographische
Korrespondenz，Band 102，Number10，
1967, feed rate as stated in P.162
and the PH, pBr and
(or) provided to maintain pAg regulation.
Using a feeding device or using a gravimetric feed
to the reaction volume through surface or subsurface supply pipes.
Can be added to the container. reaction product in the reaction vessel.
For rapid dispensing of minutes, U.S. Patent No.
No. 2996287, No. 3342605, No. 3415650,
Same No. 3785777, Same No. 4147551 and Same No.
No. 4171224, UK Patent Application No. 2022431A, Doi
TS Patent Application Publication No. 2555364 and the same No.
No. 2556885 and Research Disclosure, Vol.
166, February 1978, Item 16662
Specially configured mixing equipment may be used.
can. In the preparation of tabular grain emulsions, the dispersion medium is
Place it in a container first. in the preferred form
The dispersion medium consists of an aqueous dispersion of a deflocculant. anti
Based on the total weight of the emulsion components in the reaction vessel, from 0.2 to approx.
A peptizer concentration of 10% by weight can be adopted
Ru. Before and during silver halide formation
Based on the total weight of the peptizer concentration in the reaction vessel.
6% and maintain optimal application characteristics.
auxiliary vehicle later to obtain
The emulsion vehicle concentration can be increased by adding
A common method is to adjust the At first
5 per mole of silver halide in the emulsion formed.
~50g peptizer, preferably around 10-30g peptizer
can contain agents. additional vehicle
The concentration can be increased by adding halogens later.
Increased to a high value of 1000g per mole of silveride
can be done. Preferably finished
The concentration of vehicle in the emulsion is 1 mole of silver halide.
It is larger than 50g per serving. During the production of photographic elements
When coating and drying the emulsion layer, approximately 30~
Preferably, 70% by weight is vehicle. Vehicle (contains both binder and peptizer)
) are among those commonly used in silver halide emulsions.
You can choose from. Preferred deflocculants are hydrophilic
These are sexual colloids, and they are also sparse when used alone.
It can also be used in combination with aqueous substances. suitable
Appropriate hydrophilic substances include proteins, protein derivatives,
Cellulose such as cellulose esters
Derivatives, such as alkali-treated gelatin (beef bone)
skin gelatin) or acid-treated gelatin (pork skin gelatin) or acid-treated gelatin (pork skin gelatin)
gelatin, such as
such as chilled gelatin and phthalated gelatin
Included are materials such as gelatin derivatives. these
vehicle and other vehicles are
Research Disclosure, Vol. 176, December 1978,
Listed in Item 17643, Section. Special
Vehicle materials containing hydrophilic colloids and
Hydrophobic properties that are useful when used with these materials
The substance is present only in the emulsion layer of the photographic element according to the invention.
For example, overcoat layer, intermediate layer and
in other layers, such as those located below the emulsion layer.
Can be blended. In the process of preparing the silver halide emulsion according to the present invention
Particle ripening can occur. Particle ripening is less
In the production process of silver bromoiodide grains, the reaction volume
It is desirable that this occurs in the vessel. promote ripening
Known silver halide solvents are useful. example
For example, excessive amounts of bromide may be added to promote ripening.
is known to exist in the reaction vessel.
ing. Therefore, the bromide salt solution is added to the reaction vessel.
It is clear that ripening can be promoted simply by adding
It is. Other ripening agents can also be used.
and also before adding silver and halide salts.
All of these ripening agents are added to the dispersion medium in the reaction vessel.
You can mix the amounts in advance, or you can use one type.
Halide salts, silver salts or
can also be introduced into the reaction vessel together with a deflocculant.
Wear. Yet another variant is halogenation.
The ripening agent is separated at the stage of adding salt and silver salt.
It can also be introduced. Ammonia is a known
Highest achievable sensitivity even though it is a ripening agent
- used in emulsions of the invention exhibiting granularity relationships
It is not preferred as a ripening agent. Some preferred ripening agents contain sulfur.
be. Thiocyanate salts, e.g. alkali metals
Thiocyanate salts, especially sodium and potassium
Muthiocyanate salts and ammonium thio
Cyanate salts can be used. Thiosia
The amount of nate salt introduced can be the amount commonly used.
However, the preferred concentration is generally silver halide 1
It ranges from about 0.1 to 20 g per mole. Thiocyanene
- U.S. Patent No. 2,222,264 uses a ripening agent.
No. 2448534 and No. 3320069
Representative teachings can be seen. Otherwise, e.g.
U.S. Pat. No. 3,271,157, U.S. Pat. No. 3,574,628 and U.S. Pat.
Commonly used channels such as those disclosed in No. 3737313
Oether ripening agents can also be used. High aspect ratio tabular grain emulsions according to the invention
is preferably washed to remove soluble salts.
Removal of soluble species is carried out by Research Disclosure,
Vol, 1176, December 1978, Item 17643, Section
Decantation, as described in
such as filtration and/or cooling sedimentation and leaching.
This can be done using well-known techniques. messenger
Contains or does not contain sensitizers prior to use.
Dry the emulsion and store. The present invention
Increasing tabular grain thickness and aspect ratio
Avoid reduction in ratio and/or excessive increase in diameter
tabular grains after precipitation is complete in order to
It is especially important to wash the eggs when finishing their ripening.
advantageous to According to the tabular silver halide grain preparation method described above.
For example, tabular grains account for the entire silver halide grain population.
occupying at least 50% of the total projected area
Preparing high aspect ratio tabular grain emulsions
However, the proportion of such tabular grains
Greater benefits are achieved by increasing
It is permitted to do so. tabular silver halide
Particles occupy at least 70% of the total projected area (optimally
preferably at least 90%). Small
Even in the presence of large amounts of non-tabular grains, many photographs
Although there are no problems at all in the field of application,
To get all the benefits of tabular grains
In addition, the proportion of tabular grains can be increased.
Ru. Larger tabular silver halide grains are
The separation technique used, e.g. centrifugation or
Mixed particle collection using hydrocyclone
can be separated from the small non-tabular grains in the group.
can. Separation by hydrocyclone is done in the US
As taught in Patent No. 3,326,641. E. Controlled local epitaxy and augmentation
Thickness as indicated earlier regarding determination of aspect ratio
and tabular grains that satisfy the diameter criteria are the sensitized sites.
and these parts are related to the particle.
with a chosen orientation
This is one unique feature of the present invention.
It is a sign. In one preferred form, tabular grains
The particles are grown by epitaxial growth on those grains.
It has at least one kind of silver salt attached to it.
ing. In other words, silver salt has an oriented crystalline form.
and its orientation is determined by the crystal substrate (this
a plate-like halogen on which silver salts grow)
controlled by silver particles.
Furthermore, silver salt epitaxy is virtually selective.
Limited to exposed surface areas (local areas). Silver
Salt epitaxy takes many forms.
In the case of the present invention, each main crystal of the tabular grains
central region of the plane, annular region of each main crystal plane
and/or surrounding areas at the edges of the main crystal planes.
can be substantially limited to the area. Furthermore
In another preferred form, silver salt epitaxy
The sea is at or near the corner of the tabular grain.
can be substantially limited to an area located in
Ru. Combinations of areas as described above are also possible.
It is Noh. For example, it is limited to the central region of tabular grains.
Determined epitaxy at the corners of tabular grains
or at the edges of those particles.
Growth performed in combination with ivy epitaxy
can be set. Each of these aspects
Common characteristics led to the selection of silver salt epitaxy
Its epitaxy by localizing
of the flat halogen
At least a part of the {111} main crystal plane of the silver oxide grain
It is said to virtually eliminate silver salt epitaxy from
That is true. Although it was very unexpected, epitaxy
Selected tabular grains adhere to tabular grains through shear growth.
When limited to the area of
and Skillman “Surface structure on AgBr microcrystals”
``Structural and Epitaxial Growth'', by Jared O.
Bu Applied Physics, Volume 35, No.7,
July 1964, pp. 2165-2169.
Silver salt over the entire major surface of the sea urchin tabular grains
When randomly grown epitaxially,
It is possible to achieve improved sensitivity by comparison.
Found out. Silver salt epitaxy was chosen.
At least a portion of the main crystal plane limited to the sensitized area
substantially removes deposited silver salts by epitaxial growth.
However, in that case,
The degree of limitation of epitaxy is within the scope of the present invention.
covering a wide range unless it deviates from the
It is possible to change the Generally, the main crystal
As the amount of epitaxial growth on the surface decreases,
A greater increase in sensitivity is realized over time. workman
Silver salt deposited by pitaxial growth
is less than half the area of the main crystal plane of the tabular grain.
full, preferably less than 25%, and e.g.
Deposition of silver salt by epitaxial growth on
For certain forms such as
Less than 10% of the area of the main crystal plane of the plate-shaped particles or
It is possible to further limit the amount to less than 5%.
In some embodiments, the silver salt by epitaxial growth
When the adhesion of starts on the edge surface of tabular grains,
It was observed that. Therefore, epitaxy
In places where access is limited, if
is not performed, the selected edge sensitized areas
Epitaxy is limited and located on the main crystal planes.
This effectively eliminates epitaxy. Host of tabular silver halide (so to speak)
To create sensitized sites on the particles, epitaxial
It is possible to use silver salts deposited by growth.
Wear. The site of attachment by epitaxial growth
Through controlling the tabular host
It is possible to achieve selective local sensitization of particles.
be. “Regular” means that the sensitized areas can be predicted.
A well-ordered relationship is established for the main crystal planes of tabular grains.
and preferably mutually held.
It means that For epitaxial growth
Regarding the adhesion of silver salts to the main crystal planes of tabular grains,
By controlling the number of sensitized areas,
and horizontal spacing.
is possible. In some cases, silver halide grains increase sensitivity.
Those silver halide grains have radiation
Selective local sensitization is observed when exposed to
is formed, and the surface latent image center is formed at the sensitized area.
can be done. retains the latent image center
When developing particles in their entirety,
It is not possible to determine the location and number of latent image centers.
stomach. However, the image appears very close to the center of the latent image.
What if we can stop the development of the image before it spreads?
and then expand the partially developed particles.
If you want to take a big look at it, look at the partial development area.
You can clearly see it. these parts
The partial development area usually corresponds to the area at the center of the latent image.
Accordingly, the area at the center of the latent image generally increases.
Corresponds to sensitive areas. FIG. 2 shows a partial development sensitized according to the present invention.
This is a micrograph showing the later tabular grains. child
Can you see the things I explained earlier from the photo?
can be done. included in this micrograph
The black spots are developed silver.
The silver spreads laterally across the grain in an irregular manner.
However, what should be noted here is
is the contact point between silver and tabular grains.
point) is regular.
Ru. That is, between the contact piece and the corner of the particle
There is a predetermined relationship. Kaka
Due to the relationship between
(interval) can be taken effectively, and individual
limit the number of contact points for each particle in
can do. The regular relationship of sensitized areas illustrated in Figure 2 and
For comparison, sensitization was performed according to the present invention.
Indicates a high aspect ratio tabular grain emulsion that does not
Please refer to Figure 3. Please be careful here
What you want is to see the black spots that indicate silver development.
It's Tsuto. These spots are inside the particles.
, and are more or less randomly distributed.
ing. Contact between developed silver and particle edge
It is often seen that places are located very close together.
I can accept it. In the case of Figure 3, the sensitized site and the particle
A regular relationship exists between the main crystal planes.
I can't find out anything. For example, certain preferences as shown in Figure 2
In the case of a desirable emulsion, the regularity of the sensitized areas is
properties can be confirmed through cessation of development.
However, in many cases it is not possible to perform such corroboration.
It is impossible. For example, the formation of a latent image
The part is on or near the surface of the particle.
If it exists inside the white particle, the latent image part
difficult to establish through partial particle development
It is. This is because particles are dissolved at the same time as development.
This is because Let's look at other cases
and the sensitizing sites are themselves due to the particle geometry.
Although it is said that it is regular with respect to
A latent image area is formed in a regular manner.
Never. For example, regular sensitizing sites are
When these parts act as traps,
Captures photoholes (holes generated by light) and
prevents the extinction of electrons (photoelectrons) generated by light.
The photoholes are captured by I want to
Therefore, according to the present invention in discontinuous regular regions,
However, in sensitization, the latent image is formed in regular areas on the particle.
Is it formed at random locations or at random locations?
It has nothing to do with whether it is formed or not.
Can be done. Often at discontinuous regular sites
Selective local sensitization of the present invention is shown in electron micrographs.
It is possible to perform partial particle development.
Not as good as sea urchins. For example, refer to Figure 2 again.
Then, it is used to perform selective local sensitization.
Deposited by epitaxial growth
silver halide is attached to the corners of the tabular grains.
You can clearly see it. of the emulsion in Figure 2.
If the discontinuities located at the corners of tabular grains
A regular silver salt epitaxy is selected according to the present invention.
It acts in the direction of local sensitization. epitaxy
In situations where attachment by shear growth is limited.
directly by looking at the electron micrograph of the particle sample.
It is not possible to confirm selective partial sensitization.
stomach. In such cases, regarding precipitation of white emulsion
A certain amount of knowledge is required. In a preferred embodiment of the present invention, the specification of the present application
Prepared as previously disclosed in the book
Regular high aspect ratio tabular grain silver bromoiodide emulsions
chemically sensitize at specific particle sites. flat
The plate-shaped silver bromoiodide grains have {111} main crystal faces.
There is. First, the spectral sensitizing dye that aggregates is
adsorbed to the surface of tabular grains by photosensitization technique.
let Single molecule adsorption coverage is the lowest on all particle surfaces
about 15%, preferably at least 70%.
Use sufficient amount of dye. Color from monomolecular coverage
Although the elementary concentration can be calculated successfully, the pigment
itself is distributed uniformly on the particle surface.
It turns out that it is not as good as it is. as necessary
Accordingly, a larger amount than can be adsorbed on the particle surface
It is also possible to introduce dyes, but if an excessive amount of dye is
Even better performance when added.
This is not advantageous since it is not possible to achieve an improvement in
No, but it is possible. This will remove the pigment that aggregates.
at the sensitization stage, not because of its spectral sensitization.
chloride onto high aspect ratio silver bromoiodide tabular grains.
Its ability for direct epitaxial growth of silver
Use it for power. Therefore, epitaxy
It is possible to control adhesion by shear growth and
Other substances that can be replaced later by photosensitizing dyes
Any adsorbable species may be used.
I can do it. The function played by the pigment that aggregates is epi
affects both taxial growth control and spectral sensitization.
and also, once the dye is placed in the appropriate place.
Once done, it is unnecessary to remove it.
This is because epitaxial growth dominates.
It is clear that it is a useful substance. The agglomerating dye is adsorbed onto the surface of silver bromoiodide grains.
After that, it can be treated by conventional precipitation methods or by
Deposition of silver chloride using the Stowald thermal formation method
can be done. This epitaxial growth
silver chloride forms a shell on silver bromoiodide grains
The random attachment of
It does not form things. Such silver chloride is
Rather, adjacent to the corners of the tabular grains,
It is selectively and regularly deposited.
In general, the rate of deposition by epitaxial growth
The lower the line of such adhesion
The number of parts affected by this decreases. Therefore, it is necessary
Corner deposition by epitaxial growth
– can be limited to a level smaller than the whole
can. In the modified example, the edges of the main crystal planes
Forming a peripheral ring with silver chloride
I can do it. However, the amount of silver chloride effective for adhesion is
If there are any restrictions, this ring may be
It can be complete. For epitaxial growth
The silver chloride itself is the resultant composite grain milk.
The additional
No need to use chemical sensitization. In the particularly preferred embodiments of the present invention,
The tabular grains are silver bromoiodide grains, and
Silver chloride is epitaxially deposited at regular locations on the grains.
Attached by taxial growth. deer
However, tabular grains and silver salt sensitizers come in various forms.
can take a position. Host tabular grain
is known to be useful in the field of photography.
Any conventional silver halide composition
and high aspect ratio tabular grains
It is possible to form a child emulsion. I want to
High aspect ratio tabular grains to be sensitized
Silver chlorobromide, silver bromochloride instead of silver bromoiodide in the emulsion
or silver chloride particles may be included;
These grains optionally contain small amounts of iodide.
It's okay. Useful ratios of various halides
The rates are as described above. Sensitization of selected sites on host tabular grains
The purpose is to attach a silver salt for
Salt selection is usually based on the etching on the silver halide grains.
The field of photography where pitaxial growth is possible
Although it is conventionally known to be useful in
You can do it from inside. Silver salt and flat
Sufficient anion content in plate-shaped silver halide grains
are different, and therefore each of them
It is possible to recognize differences in their crystal structures.
Surprisingly, tabular grains and corner or edge
Is the silver halide composition the same as that of the azalea deposits?
Even in cases where the adsorbed local area
flat plate in the presence of a site director
When forming deposits on shaped host particles,
Observe the growth of non-tabular corners and edges.
I was able to Silver salts and tabular silver halides
If the anion content of the particles is different or the same,
Even if there is a difference, the modifier that is present (mixed in)
to exist in one or both of them
Can be done. silver salt, core-shell silver halide
be useful in forming emulsion shells
You can choose from among the previously known ones.
Wear. All known photographically useful silver salts
In addition to silver halide, on silver halide grains
Other known precipitate-forming
Silver salts, such as silver thiocyanate, silver phosphate, cyanide
Silver compound, silver carbonate, etc. can be encapsulated.
Ru. Such silver salts are intended as selected silver salts.
Depending on the application, tabular silver halide grains
Any modifying compound as described above in connection
can be attached advantageously in the presence of
Ru. Halogen forming tabular grains of the host
Some silver oxides are usually grown by epitaxial growth.
In the process of forming deposits, they enter the solution.
and mixed into silver salt epitaxy.
Ru. For example, halogenation on silver bromide host grains
Silver deposits usually contain a small percentage of bromide ions
will contain. Therefore, the host
grown epitaxially on plate-like grains
When referring to a specific silver salt as
It is different when the host
The tabular grains also have the same composition.
The existence of species silver halide
I'm not trying to eliminate it. Typically, the host tabular grain silver halide
silver salt exhibits higher solubility compared to
However, it is advantageous for convenience. If you do this,
Dissolution of the tabular grains occurs during the deposition of silver salt.
This can reduce the tendency for this to occur. In this case, the tabular grain
Just like that to minimize child dissolution.
Limiting sensitization to conditions that
For example, silver halide with greater solubility
Silver salts with poor solubility are deposited on tabular grains.
Restrictions such as those required when attaching
can be avoided. host tabular grains
Advantageously, it consists essentially of silver bromoiodide.
Ru. This is because when looking at silver bromoiodide,
It is compared to silver bromide, silver chloride or silver thiocyanate.
Each of these salts has a relatively poor solubility and
It can easily act as a host when attaching
This is because it is possible. On the other hand, silver chloride is
It has higher solubility than silver oxide or silver bromide.
Since there are
Easily epitaxy onto tabular grains consisting of
It can also be selectively grown locally
It can be an advantageous silver salt for sensitization.
In most cases, it has poor solubility compared to silver chloride.
However, compared to silver bromide or silver bromoiodide,
Salt silver thiocyanate which has great solubility
It can be used in place of silver oxide. However,
However, for maximum stability, thiothia
Silver chloride is usually preferred over silver phosphate.
More soluble nontabular silver halide hosts
Epitaxy of less soluble silver salts onto particles
This technical field is capable of attaching by means of yarn growth.
It has been reported in
This can be used in the practice of the invention.
Wear. For example, epitaxial silver bromoiodide on silver bromide.
Deposited by shear growth or silver chloride
Depositing silver bromide or silver thiocyanate on top
I can do it. multilevel epitaxy
That is, silver salt epitaxy is provided on another silver salt,
In addition, this silver salt itself can be etched onto host tabular grains.
Attachment by pitaxial growth,
It is possible to implement For example silver bromoiodide or silver bromide
Epitaxial growth of silver chloride on host grains
Then, further etch silver thiocyanate onto this silver chloride.
Pitaxyial can be grown. Wide controlled local epitaxy
A range of epitaxial growth silver salt concentrations reached
can be achieved. Contained in composite sensitized particles
approximately 0.05 mol% based on the total amount of silver
Increased sensitivity when applying low silver salt concentrations
can be achieved. On the other hand, 50 mol
The highest level when applying silver salt concentrations of less than %
sensitivity can be achieved. Usually epitaph
The concentration of silver salt deposited by crystallization is
Advantageously, it is between 0.3 and 25 mol%, and
For sensitization, such concentrations are approximately 0.5-10
Mole % is generally optimal. Adsorbed locally dominant substances, e.g. agglomerates
The dye to be used depends on the silver salt to be used and the {111}
Halide content in tabular grains exhibiting crystal planes
It can be excluded depending on the amount, and also
Controlled local epitaxy regardless of
can be achieved. host tabular grains
Essentially at least 8 mol% iodide on its surface
(preferably at least 12 mol% iodide).
absence of adsorbed locally dominant substances.
at the corners of its host tabular grains
Selective epitaxial growth of adjacent silver chloride
will be carried out. Surprisingly, silver chloride epi
Prior to taxial growth. like 1 mol%
Mixing low concentrations of iodide into tabular silver bromoiodide grains
tabular silver bromide or silver bromoiodide grains to
Similar results occur when contacting with aqueous iodide salts.
can achieve results. adsorbed
In the absence of a locally controlling substance, the
The edges of the tabular silver halide grains of the composition
selectively etch silver thiocyanate at
Pitaxyial can be grown. host
These are composed of tabular grains and a silver salt sensitizer.
In the case of a conjugate, the adsorbed local substances
that it is unnecessary to use quality
epitaph at the corners or edges of
In order to more narrowly limit the growth of
It is often advantageous to use adsorbent locally dominant substances.
be. High aspect ratio tabular silver bromoiodide grains
It is an annular region surrounding the area laterally.
or in areas that are otherwise horizontally arranged.
lower concentration of iodide in the central region than in the
It is possible to use particles that contain
Wear. The horizontally surrounding annular region is the
Low 8 mol% (preferably at least 12 mol%) surface
iodide concentration, and the central region is 5 molar.
If it contains less than % iodide, the adsorption
Tabular bromoiodination without the use of localized substances
Confining the sensitization of the silver particle to the central region of its center
be able to. Or make a different point.
Then, selective epitaxy in the central grain region
In the case of circular growth, the particles present on the surface of the annular particle region
The iodide produced by itself is capable of selective epitaxial formation.
Can act as a local control substance for long
Ru. relative to the laterally surrounding annular particle region.
If we limit the size of the central particle region by comparing
Just by applying such restrictions, the area of sensitization can be reduced.
can be restricted. In this way selective
One clear advantage of the method of local sensitization
There is a central location of the sensitized site. places like this
When photoelectrons or photoholes reach the sensitized site,
The diffusion process required can be shortened.
Therefore, holes and electrons are at risk of being annihilated.
can trap more effectively under conditions of less
can. in the direction in which the sensitized region positions the latent image.
If it works, by reducing the number of sensitized sites
This can reduce competition for photoelectron capture.
Wear. This method of selective local sensitization is based on chloride
Where silver is deposited by epitaxial growth
This is useful when In another variant of the invention, the suction
The use of locally controlled substances is unnecessary and
When using a tabular silver bromoiodide emulsion as described above,
Ru. Tabular silver bromoiodide grains are
It has an iodide-poor central region and this
such that the region is itself a circular region.
select. That is, such tabular grains have no odor.
Main central region consisting of silver iodide, iodide content
a laterally surrounding central region with a slight
contains a peripheral annular region laterally surrounded by
ing. As mentioned earlier, the annular central region is
Contains less than 5 mol% iodide, and
The central region and the annular peripheral region that occupy the majority are
each at least 8 mol%, preferably at least 12 mol%.
Contains iodide. Silver chloride is a tabular grain
defined by the annular central region among the main crystal planes of
Epitaxial growth on multiple parts
and are substantially limited to those parts.
Ru. Controlling the extent of the central annular region
epitaxial growth on major surfaces of tabular grains through
Control the degree of taxial growth accordingly
can do. Of course, silver chloride epitaph
In cases where the amount of axial growth is limited, annular
of the allowable adhesion surface area provided by the central region.
Epitaxy does not necessarily occupy all of the space.
If necessary, deposit silver chloride within the annular center area.
can be limited to a few discontinuous parts of
Ru. Absence of central region with low iodide content
Alternatively, epitaxial growth
against the corners of tabular silver bromoiodide grains for
Silver chloride can be given. Silver chloride is the center
It is said that it is preferentially deposited in areas where
That is amazing. Sufficient silver chloride deposition speed
chloride if it can be promoted to
silver in both the central and peripheral regions of the tabular grains.
It is possible to attach it at the location. Silver salts can be used for silver salt epitaxy or tabular halogen
Hole trapping depends on the composition of silveride host particles.
act as a trap or as an electronic trap.
sensitize by either
be able to. In the latter case, imagewise exposure
Silver epitaxy positions the latent image area formed by
It is also possible to decide. Silver salt epita
It exists as a sensitivity improver in the crystal growth process.
Modifying compounds such as copper, thallium,
Lead, bismuth, cadmium, zinc, intermediate calco
gen (i.e. sulfur, selenium and tellurium),
Gold and noble group metal compounds enhance sensitization
It is especially useful for electronic trap gold
When ions of the genus are present in silver salt epitaxy,
It is useful in helping to form an internal latent image
be. For example, one particularly preferred embodiment of the present invention is shown.
In this case, relatively high iodide compounds such as those mentioned above
Helps trap electrons in the center of silver bromoiodide tabular grains.
Modifying compounds such as lead or iridium compounds
silver chloride may be deposited in the presence of
Ru. After imagewise exposure, silver chloride in the tabular grains
Pitaxy is internalized at the doped sensitized site.
A latent image area is formed. Deposition and assembly by epitaxial growth of silver salts
silver salt to help form a combined internal latent image.
Halide conversion after epitaxial growth of
(conversion)
There is one way. For example, epitaxial
When the salt deposited by the length is silver chloride,
If this salt is combined with a halide of low solubility, e.g.
Contact with bromide salts or mixtures of bromide and iodide salts
It can be modified by touching it.
As a result, epitaxial growth deposits
The chloride in it is bromide, and if there is
If so, it is replaced by iodide ions. this
The defects on the crystal obtained in this way are in the form of internal latent images.
It is thought that this is the basis for the formation of epitaxy
Halogenation of salt deposits due to slug growth
For example, performing the transformation of things is
No. 4,142,900. In the various aspects of the present invention described above,
Discontinuous silver salt epitaxy on tabular host grains
limit to the following parts, e.g. center or corners
Or at the edge of the main crystal plane, for example
A ring such as a peripheral ring can be formed.
Silver salt epitaxy can only function as an electronic wrap.
To achieve this, positioning of the latent image on the particle is performed.
If the epitaxy is
For example, it may be limited to the center of the main crystal plane.
should be placed adjacent to the corner of the tabular host grain.
is preferable. In this case, the latent image area is densely
are formed and therefore deprived of photoelectrons.
The opportunity for this to occur is that the latent image area is a tabular grain.
If it can be formed along the edge of the child (tabular
The particles are surrounded by a ring of silver epitaxy.
(which can occur if
I can't stand it. Silver salt epitaxy on tabular host grains
Acts as a child trap or acts as a hole trap
can act as a tup, and therefore,
Silver salt epitaxy acts as a hole trap
and silver salt epitaxy acting as an electron trap.
- are combined to form a complementary sensitizing conjugate.
It turns out that it can be done. For example, electronic
When using lapping silver salt epitaxy,
tabular host grains at the center of their grains or
can be selectively sensitized near the
a. After that, hole-trapping silver salt epitaxy
selectively adheres to the corners of particles.
can be set. In this case, the electronic truck
A latent image in the center of the epitaxy site
is formed, and also by corner epitaxy.
further increases the sensitivity (otherwise photovoltaic
A photohole is trapped that will inevitably destroy all children.
). Let's take a look at the typical forms in particular.
And, as mentioned earlier, in less than 5 mol% of iodide
contains the core region and the remainder of the main crystal planes are the most
Contains as low as 8 mol% iodide, preferably 12 mol%.
chloride on silver bromoiodide tabular grains with
Epitaxial growth of silver is performed. silver chloride
is a modifying compound that helps electron trapping, e.g.
Compounds that provide lead or iridium dopants
epitaxial growth in existence
Ru. After that, hole-trapping silver salt epitaxy
is selected at the corner of the host tabular grain.
Can be selectively attached or adsorbed
The main crystal planes are
selectively attached as a ring along the edge
It can be done. For example, thiocyanin containing copper-based dopants
silver chloride or silver chloride deposited on host tabular grains
can be done. Other combinations are also
Of course it is possible. For example, as shown above
When replacing the position of a modifying substance such as
The epitaxy of
In addition, at the corners of the host tabular grains
The epitaxy that occurs acts as an electron trap.
can be done. The above describes the selective control of epitaxial growth of silver salt.
Although I have explained about partial sensitization, silver halide
Controlled localized epitaxial growth
It can also be useful in other ways.
It will be understood that For example, epitaph
Aggressively grown silver salts can be used as insulators in tabular grain emulsions.
Improving incubation stability
Can be done. Such silver salts may also be partially grained.
For promoting secondary development and amplifying dye images
may also be useful, as detailed below.
Can be done. Epitaxially grown silver salts are also
It can relieve the desensitization of pigments. moreover,
Such silver salts can also promote dye aggregation.
can. This removes most of the silver bromoiodide crystal surface.
by leaving it substantially free of silver chloride.
It is possible. This is because many of the aggregated dyes
silver bromoiodide compared to the surface of silver chloride grains.
This is because it can be effectively adsorbed. here
Another advantage that can be realized is improved
This is the developed ability. In addition, localized
Even higher contrast can be achieved through pitaxy.
can be used. Regular chemical sensitization is controlled by silver salt.
may be used prior to localized epitaxial growth.
can be carried out in subsequent steps.
Ru. Silver chloride and/or silver thiocyanate
When deposited on silver oxide, only selective deposition of the silver salt
Achieving a significant increase in sensitivity simply by attaching
can do. Therefore, the photographic sensitivity is
Subsequent chemical sensitization of the type commonly used to
It is unnecessary to carry out the process. on the other hand
For subsequent chemical sensitization, additional
A significant increase in sensitivity can generally be obtained. here
When finishing the emulsion, high temperatures also require long residence times.
One of the benefits is that time is unnecessary.
This is a great advantage. (1)Epitaxial growth
or (2) if the sensitization is episodic.
If directed to the taxial growth site, the increase
The amount of sensitizer can be lowered as needed.
Silver chloride epitaxial growth without further chemical sensitization
When taxial growth was carried out, a tabular odor was formed.
Virtually the highest sensitization achieved for silveride emulsions
It was done. If silver bromide is epitaxied on silver bromoiodide,
If you want to make the skin grow, selectively localize it.
Following adhesion, further chemical sensitization is performed and
Apply customary finishing times and temperatures.
Large increases in sensitivity can be achieved in some cases.
can. Adsorbed seshimera itself is an effective spectral sensitizer
using localized substances, e.g. agglomerating dyes.
If so, chemical sensitization followed by spectral sensitization
The process is unnecessary. However, various
If you look at the case, it may be chemically sensitized.
can be followed by spectral sensitization.
Ru. Spectroscopy as locally dominant substances adsorbed
If no sensitizing dye is used, e.g.
Aminoazaindene (e.g. azaindene) as the dominant substance
denine), perform spectral sensitization.
If so, continue with chemical sensitization. Adsorb it
If the locally dominant substance itself becomes spectral sensitizer
If not a dye, the spectral sensitizer is
It may be something that can replace the dominant substance.
or at least close enough to perform spectral sensitization.
The particle surface must be accessible at
do not have. In many cases, adsorption
Using the spectral sensitizing dye as a local controlling substance
spectral sensitization followed by spectral sensitization.
It is still desirable to carry out a photosensitization step. Bureau
The spectral sensitizing dye used as the dominant substance
Additional spectral sensitizing dyes may be used instead.
Or you can replenish it. For example,
Additional spectral gain when using additional sensitizing dyes
or, most preferably, hyperincrease.
Spectral sensitization can be sensitively increased. Of course
The spectral sensitizer introduced after optical sensitization is chemical
Whether it can act as a locally controlling substance for sensitization
This means that it is not important.
Dew. Controlled localized epitaxial growth
After that, use any conventional chemical sensitization method.
Can be done. In general, the composition of the host tabular grains
It also serves as a base for the silver salt to which it is attached.
Chemical sensitization should be performed. That's what I mean
The first place where chemical sensitization occurs is silver salt.
At the site of attachment or perhaps at such site
This is because it is considered to be a place where you can do it directly. High aspect ratio tabular grain halogens of the present invention
Silver oxide emulsions are deposits caused by epitaxial growth.
Chemically sensitize before or after formation of
be able to. Chemical sensitization is James
(TH James), The Theory of the
Photographic Process, 4th Ed., Makrami
Activities as described in John, 1977, pp.67-76.
It can be done using gelatin or
Research Disclosure, Vol.120, 1974
April, Item12008, Research Disclosure,
Vol.134, June 1975, Item13452, US Patent
No. 1623499, No. 1673522, No. 2399083,
Same No. 2642361, Same No. 3297447 and Same No.
3297446, British Patent No. 1315755, US Patent No.
No. 3772031, No. 3761267, No. 3857711,
Same No. 3565633, Same No. 3901714 and Same No.
3904415 and described in UK Patent No. 1396696
For example, pAg level 5-10, PH level
5 to 8, and sulfur at a temperature of 30 to 80°C,
Selenium, tellurium, gold, platinum, palladium, iris
Dium, osmium, rhodium, rhenium
or using a phosphorous sensitizer or a combination of these sensitizers.
It can be done by Chemical sensitization is optimally
As described in U.S. Patent No. 2,642,361
2×10 based on silver ^-3 Chi at a concentration of ~2 mol%
In the presence of oceanate compounds, the US
Permit No. 2521926, No. 3021215, and No. 3021215
Sulfur-containing compounds of the type described in No. 4054457
Perform in the presence of an object. Finishing (chemical sensitization) modifier
Chemical sensitization can be performed in the presence of
Ru. The finish modifier used may be e.g.
ndene, azapyridazine, azapyrimidine,
ndzothiazolium salt, and one or more
Chemical sensitizers, such as sensitizers with heterocyclic nuclei
Suppresses fogging when present during the printing process and
A compound known to increase sensitivity.
Examples of finish modifiers include U.S. Patent No. 2,131,038;
Same No. 3411914, Same No. 3554757, Same No. 3565631
No. 3901714, Canadian Patent No. 778723
and Duffin, Photographic
Emulsion Chemistry, Focal Press
(1966), New York, pp. 138-143.
has been done. In addition to or instead of chemical sensitization
As such, U.S. Patent No. 3891446 and U.S. Patent No. 3984249
For example, using hydrogen, as described in No.
Also, US Patent No. 2983609 Research
Disclosure, Vol. 136, August 1975,
Item 13654, U.S. Patent No. 2518698, same no.
No. 2739060, No. 2743182, No. 2743183,
Described in No. 3026203 and No. 3361564
So, stannous oxide, thiourea dioxide, polyamine
and with reducing agents such as amine borane.
or low pAg (e.g. less than 5) and/or high pAg.
Reduction sensitization by PH (e.g. greater than 8) treatment
can be done. U.S. Patent No. 3917485
and subsurface sensitization described in No. 3966476.
Including surface chemical sensitization can be performed. In addition to chemical sensitization, the high aspect ratio of the present invention
Spectral sensitization of tabular grain silver halide emulsions
You can also do it. Blue and negative of the visible spectrum
exhibiting an absorption maximum in the blue (i.e., green and red) region;
Spectral sensitizing dyes can be used. In addition,
In special fields of application, spectral sensitizing dyes are used to
Improved spectral response beyond the visible spectrum
can do. For example, infrared absorption spectral sensitization
It is possible to use agents. The silver halide emulsions of the present invention are of various classes.
Spectral sensitization can be performed using these dyes.
The classes of dyes used here include cyanide.
merocyanine, complex cyanine and complex merocyanine
cyanines (i.e., trinuclear-, tetranuclear-, and polynuclear cyanines)
and merocyanine), oxonol, hemioxol
sonor, styril, merostyril and stre
Contains polymethine pigments including ptocyanin
Ru. Cyanine spectral sensitizing dyes include, for example, quinolini
um, pyridinium, isoquinolinium, 3H
- indolium, benz[e] indolium,
oxazolium, oxazolinium, thiazoli
um, thiazolinium, selenazolium, sele
nazolinium, imidazolium, imidazolini
um, benzoxazolinium, benzothiazo
Lium, benzoselenazolium, benzimida
Zolium, naphthoxazolium, naphthothia
Zolium, naphthoselena zolium, thiazolini
dihydronaphthothiazolium, pyriliu
derived from imidazopyrazinium quaternary salts and imidazopyrazinium quaternary salts.
2 bound by a methine bond, such that
It contains two basic heterocyclic nuclei. Merocyanine spectral sensitizing dyes include, for example,
Bitturic acid, 2-thiobarbituric acid, rho
Danine, hydantoin, 2-thiohydantoy
4-thiohydantoin, 2-pyrazoline-
5-one, 2-isoxazolin-5-one, i
Ndan-1,3-dione, cyclohexane-
1,3-dione, 1,3-dioxane-4,6
-dione, pyrazoline-3,5-dione, pen
Tan-2,4-dione, alkylsulfonyla
Setonitrile, arononitrile, isoquinoline
-4-one and chroman-2,4-dione
Acidic nuclei and cyanine pigments such as those that can be induced
The basic heterocyclic nucleus of i.p.
Includes combined items. Using one or more spectral sensitizing dyes
I can do it. Wavelengths across the visible spectrum
has maximum sensitivity and is extremely versatile.
Dyes with spectral sensitivity curve shapes are known.
Ru. The selection and relative proportions of dyes are desirable for sensitization.
region of the spectrum desired and the desired fraction.
Depends on the shape of the photosensitivity curve. Overlapping spectral sensation
Dyes with a degree curve often
The sensitivity at each wavelength is the sum of the individual sensitivities.
will show curves of approximately equal combined shape.
cormorant. Therefore, multiple colors with different maximum sensitivities
Individual colors can be created by combining elements.
Spectral sensitivity with maximum value midway between the original maximum sensitivity
You can get a curve. Using multiple spectral sensitizing dyes in combination
and thereby supersensitize
(Supersensitization), that is, in a certain spectral region.
In some cases, one of these spectral sensitizing dyes is used alone.
greater than when used at any concentration.
and the additive effects of those spectral sensitizing dyes.
spectral sensitization that is greater than the sensitization derived from
can be achieved. Supersensitization is spectrally sensitized color
and other additives such as stabilizers and carbon.
Anti-blur agents, development accelerators or inhibitors, coating aids
selected combinations of whitening agents, brighteners and antistatic agents.
This can be achieved by The key to supersensitization
Some mechanisms and compounds that may be responsible
All of them are Gilman's ``supersensitizer''.
Review of the Mechanisms of
Supersensitization)”, Photographic Science
and Engineering, Vol, 18, 1974, pp.
418-430. Spectral sensitizing dyes also affect emulsions in other ways.
I can do it. In addition, the spectral sensitizing dye is
As disclosed in No. 2131038 and No. 3930860
halogen acceptor or electron acceptor, anti-fogging
inhibitors or stabilizers, and development accelerators or inhibitors
can act as. In one preferred form of the invention, spectral sensitization
Pigments are also adsorbed locally dominant substances.
During silver salt deposition or chemical sensitization,
do. Useful pigments belonging to this type are agglomerated colors
It is basic. Such dyes are halogenated
Function of being adsorbed onto the surface of silver oxide particles
As a result of light absorption due to bathochromic and hypsochromic effects,
Presenting an increase. Colors that meet these criteria
For example, TH James, The Theory of
the Photographic Process, 4th Ed., Ma
Cumilan, 1977, Chapter 8 (especially F.
Induced Color Shiftin Cyanine and
Merocyanine Dyes) and Chapter 9 (especially
H.Relations Between Dye Structure and
Surface Aggregation) and FMHamer,
Cyanine Dyes and Related Compounds, Di
Yong Willie and Sons, 1964, Chia
Pter-X (especially F.Polymerization and
Sensitization of the Socond Type)
well-known in this technical field, as
It is. H aggregate (shift due to hypsochromic effect)
For example, merocyanine, hemicyanine, which forms
spectroscopy such as n, styryl, and oxonol
Sensitizing dyes are known in the art.
However, for these classes of dyes, J aggregates
(shift due to bathochromic effect) is not common. good
Preferred spectral sensitizing dyes are cyanine dyes. and
This is because, in the case of this dye, H aggregates or
This is because it exhibits any of the J aggregates. Carbosia is a preferred form of spectral sensitizing dye.
There is a nin dye (which exhibits J aggregates). child
Pigments such as are composed of two or more complex
The cyclic nucleus is formed by a bond consisting of three methine groups.
It is characterized by being combined. heterocycle
The formula nucleus is preferably
contains a fused benzene ring. Promote J aggregation
A preferred heterocyclic nucleus for proceeding is quinoliniu
Benzoxazolium, Benzothiazolium
Mu, benzoselenazolium, benzimidazoli
um, naphthoxazolium, naphthothiazolium
um, and naphthoselenazolium quaternary salt.
be. Used as an adsorbed locally dominant substance.
Particularly preferable dyes for coloring are listed below.
As described in Table I. Table I Preferred example of adsorbed locally dominant substance AD-1 Anhydro-9-ethyl-3,3'-bi
Su(3-sulfopropyl)-4,5,
4′,5′-dibenzothiacarbocyanine
Hydroxy AD-2 Anhydro-5,5'-dichloro-9-
Ethyl-3,3'-bis(3-sulfobyl)
Chill) thiacarbocyanine hydroxy
AD-3 Anhydro-5,5',6,6'-tetra
Chloro-1,1'-diethyl-3,3'-
Bis(3-sulfobutyl)benzimine
Dazolocarbocyanine hydroxide AD-4 anhydro-5,5',6,6'-tetra
Chloro-1,1',3-triethyl-
3'-(3-sulfobutyl)benzimine
Dazolocarbocyanine hydroxide AD-5 anhydro-5-chloro-3,9-di
Ethyl-5'-phenyl-3'-(3-st)
Lufopropyl) oxacarbocyanine
Hydroxide AD-6 Anhydro-5-chloro-3,9'-di
Ethyl-5'-phenyl-3-(3-st)
Lufopropyl) oxacarbocyanine
Hydroxide AD-7 Anhydro-5-chloro-9-ethyl
-5'-phenyl-3,3'-bis(3-
sulfopropyl) oxacarbocyani
Anhydrohydroxide AD-8 Anhydro-9-ethyl-5,5'-di
Phenyl-3,3'-bis(3-sulfo)
butyl) oxacarbocyanine hydro
Oxide AD-9 Anhydro-5,5'-dichloro-3,
3'-bis(3-sulfopropyl)thia
Cyanine hydroxide AD-10 1,1'-diethyl-2,2'-cyanine
p-Toluenesulfonate Record blue light exposure in this technical field
If such records are intended to be made
In the emulsion layer, silver bromide or silver bromoiodide is usually used.
Although it depends on the original blue sensitivity, if the emulsion
Main absorption is seen in the spectral region that shows sensitivity.
Even in cases where the use of spectral sensitizers
can provide important benefits. For example, blue
Advantages are achieved through the use of color spectral sensitizing dyes.
It is particularly recognized that Emulsion according to the present invention
High aspect ratio tabular grain silver bromide and bromoiodide
Blue spectral sensitizing dyes, even in silver emulsions
A very large increase in sensitivity is obtained by the use of
be able to. The emulsion according to the invention can be
When intending to expose in the sensitivity range
by increasing the thickness of the tabular grains.
advantage in sensitivity can be obtained. example
For example, in one preferred form of the invention, the emulsion is
Blue sensitized silver bromide and silver bromoiodide emulsions, and
In such emulsions, the thickness of less than 0.5 micrometers
full and at least 0.6 micrometers in diameter
The tabular grains have a ratio of greater than 8:1, preferably
Has an average aspect ratio of at least 12:1,
All of the silver halide grains present in the emulsion are
At least 50% of the projected area, preferably 70%, especially preferably
Preferably, it accounts for at least 90%. Spectroscopy useful for sensitizing silver halide emulsions
Some sensitizing dyes include Research Disclosure, Vol.
176, December 1978, Item 7643, Section
There is something to be posted. Non-planar or low aspect ratio
Spectroscopy of the emulsion layer containing plate-like silver halide grains
To sensitize, use a commonly used amount of dye.
I can do it. In order to realize the full advantages of the present invention,
the optimum amount of particles (i.e. under possible exposure conditions)
at least 60% of the maximum photographic sensitivity achievable from
high-altitude spectral sensitizing dye (in sufficient amount to achieve
Spectral ratio Absorption on the grain surface of tabular grain emulsions
It is preferable to tighten it. The dye used here
The amount depends on the particular dye or set of dyes selected.
alignment and particle size and aspect ratio.
will vary based on. surface photosensitive halogen
Approximately 25 to 100% of the total effective surface area of silver oxide particles or
is organic at a monolayer coverage equivalent to
Optimal spectral sensitization is achieved when dyes are used.
This is known in the photographic field.
That is, this means that, for example, the waist
et al., “Adsorption of sensitizing dyes in photographic emulsions (The
Adsorption of Sensitizing Dyes in
Photographic Emulsions)” Journal of phys.
Chem., Vol.56, p.1065, 1952; Spence
(Spence) et al. “Desensitization of sensitizing dyes”
(Desensitization of Sensitizing Dyes)”
Journal of Physics and Colloids
Chemistry, Vol.56, No.6, June 1948,
pp. 1090-1103; and U.S. Pat. No. 3,979,213.
It is listed. The optimal dye concentration level is
Mees, Theory of Photographic Process,
1942, Macmillan, pp. 1067-1069 (ibid.)
You can choose according to the method taught.
Ru. Although it was completely unexpected, according to the present invention,
High aspect ratio with selective local sensitization
The ratio of tabular grain silver halide emulsions is similar to that of
high aspect ratio tabular grain silver halide emulsions
(Chemical sensitization and spectroscopy according to conventionally known techniques)
When compared with the one for which sensitization has been completed,
It was found that the camera exhibits high photographic sensitivity.
Ta. High aspect ratio tabular grain bromoiodination of the present invention
Silver emulsions have traditionally been observed in the field of photography.
Higher sensitivity compared to conventional granularity relationship
Present. Necessary to achieve all benefits
However, the emulsion according to the present invention
Optimum chemical and spectral sensitization can be achieved by following conventional manufacturing methods.
It is preferable that This means that possible uses
in the sensitized spectral region under application and processing conditions.
of the maximum log sensitivity achieved from those particles
Achieve a sensitivity equivalent to at least 60%
means that it is preferable. Here, log sensitivity
means 100 (1-logE), and E in the formula is
m-can at a density of 0.1 above fog
It is the exposure amount expressed in dollars-seconds. emulsion layer
Once the host tabular grains have been characterized,
The emulsion layer of the product is comparable to that of other manufacturers.
Optimally chemically and spectrally sensitized for
Further product analysis and performance evaluation to determine whether
This can be determined by doing the following. main departure
In achieving the benefits of brightness and sharpness,
Spectral sensitization or spectral sensitization of silver halide emulsions
Is it done efficiently or is it done inefficiently?
It doesn't matter what it is. F Silver image formation As mentioned above, once high silver
Formation and washing of spectral tabular grain emulsions
and once sensitized, it can be used for commonly used photography.
Their preparation can be completed by blending additives.
can be completed. And these are silver statues
Photography application field that sought what should be generated, an example
For example, it can be applied to ordinary black and white photography. Using a photographic element having an emulsion according to the invention
Photographs of silver statues if they are intended to form
The elements are compounded with additional hardener during processing.
The membrane can be sufficiently hardened so that it is not necessary.
Ru. This hardening increases the covering power of silver.
can realize an increase in A typical useful compound hardener (pre-hardener) is Ri
Search Disclosure, Volume 176, 1978
December, Item 17643, Section X. Research Disclosure, Volume 176,
December 1978, Item 17643, Section
stabilizers, antifoggants, anti-kink agents, etc.
emulsifiers, latent image stabilizers and similar additives before application.
By mixing into the agent layer and the adjacent layer, negative tone
Increases the minimum density (i.e. fog) in emulsion coatings.
Large or minimum in direct positive emulsion coatings
Increase the concentration or reduce the maximum concentration
can be freed from the instability caused by CEK
Mees, The Theory of the F
Autograph Process, 2nd edition, Makumi
As described in Lan, 1954, pp. 677-680,
An effective antifogging agent for emulsions as they are emulsified.
Many of these can also be incorporated into developers, or
They can be classified under a few general headings.
I can do it. When using aldehyde type hardeners,
The emulsion layer can be protected with a commonly used antifoggant.
can. In the case of the emulsion of the present invention, a negative image or a positive image
Apply it equally to the photographic element intended to form
can be used. For example,
A photographic element having an emulsion layer such as
Shape either a surface or internal latent image with light
These latent images can also be processed into negative images.
It can be of such type as to form.
In some cases, such photographic elements are
A type that directly forms a positive image in response to the process.
It can be ip. host tabular grains and
Composite particles consisting of silver salt epitaxy
When forming an image, directly promote the formation of a positive image.
A surface charge is applied to these composite particles for the purpose of
You can give yellowtail. Particularly preferred type 1
In this case, the silver salt epitaxy itself
form a latent image region (i.e., transport electrons inside)
Select that epitaxy in the direction of
Also, if necessary, remove the surface fog from the silver.
Can be limited to salt epitaxy. already
In one form, the host tabular grains are preferably
In particular, the silver salt epitaxial layer acts as a hole trap.
Trap electrons internally with taxi
can be done. Emulsion with a superficial fog
Can be used in combination with organic electron acceptors
can. This is true, for example, in U.S. Patent No.
2541472, UK Patent No. 723019, US Patent No.
No. 3501305, No. 3501306 and No. 3501307,
Research Disclosure, Volume 134, 1975
June, Item 13452, and U.S. Patent No.
No. 3672900, No. 3600180 and No. 3647643
It is described in. Described in U.S. Patent No. 3501310
Spectrally sensitized organic electron acceptors as shown in
Either use it in combination with the original or the former.
can be a spectral sensitizing dye. if
It also uses an internally sensitive emulsion.
If so, it is described in U.S. Patent No. 3501311.
Combining sea urchin surface fogging agent and organic electron acceptor
Can be used together. However, direct positive
If you want to form an image, a surface fogging agent may also be used.
Electron acceptors are also unnecessary. Photographic elements having emulsions of the present invention are described above.
In addition to special features such as research
Disclosure, Volume 176, December 1978,
Regular features as described in Item 17643
can be used. Using the emulsion of the present invention
The use of photographic elements in the field of radiography
of the radiographic element if you intend to
Research that allows emulsions and other layers to be cited first
Disclosure, Volume 184, August 1979,
In any form specifically described in Item 18431
It can also be set as Emulsion arrangement according to the present invention
Other commonly used silver halide elements in photographic elements
Contains agent layer, intermediate layer, overcoat and undercoat layer.
If so, these are the research disks.
Rosier, Volume 176, December 1978, Item
17643, applied as described in Section XV, and
Can be dried. In accordance with established practice among those skilled in the art, the present invention
High aspect ratio tabular grain emulsions related to
Or blend these with commonly used emulsions.
specific properties required of the emulsion layer by
can be satisfied. For example, multiple
By blending emulsions, a given purpose can be achieved.
Adjust characteristic curves of photographic elements to your satisfaction
be able to. By blending, exposure and processing
increases the maximum concentration achieved by
is reduced, the minimum concentration is reduced or increased,
and adjust the shape of the characteristic curve between the foot and shoulder.
can be done. For this purpose, the emulsion according to the present invention
Research disclosure that can be cited first
-, Volume 176, December 1978, Item 17643, Section I
Commonly used silver halide milks as described in
Can be blended with agents. Also, I term F
It is also possible to blend emulsions such as those described in
It is possible. Photographic elements having emulsions according to the invention are most
For simple forms, high aspect ratio according to the invention
Single silver halide emulsions including tabular grain emulsions
using a layer and a photographic support. Of course, more than 2
The upper silver halide emulsion layer and overcoat
Advantageously, it may contain a base coat layer and an interlayer layer.
is recognized. Blend the emulsion as described above.
The emulsions to be blended can be
Similarly, by applying each as a separate layer.
effects can be achieved. Separate emulsion layers
It is possible to obtain exposure latitude by applying the photo
Well known in the technical field, Zerikmann
(Zelikman) and Levi (Levi), making/
and coating photography
Emulsions Focal Press, 1964,
pp.234-238, U.S. Patent No. 3,663,228 and British Patent No.
It is described in Permit No. 923045. In addition, high sensation
In blending high and low sensitivity silver halide emulsions
photographic sensitivity by coating in separate layers without
In the field of photographic technology, it is possible to increase
It is well known. Usually, the high-speed emulsion layer is replaced with the low-speed emulsion layer.
It is applied closer to the exposing radiation source than the layer.
This technique consists of three or more stacked emulsions.
It can be applied to the preparation of layers. like this
Layer configurations can be utilized in the practice of the present invention.
Ru. Coating layers of photographic elements onto various supports
I can do it. Typical photographic supports include polymers
films, wood fibers (e.g. paper), metal sheets and
Bicarbonate, glass and ceramic supports
These are the adhesive properties of the support surface, the band
Antistatic property, dimensional stability, wear resistance, hardness, friction
properties, antihalation properties and/or its
Under 1 or 2 or more conditions to improve other properties
It can have a coating layer. These supports are
Well known in the art, e.g.
Disclosure, Volume 176, December 1978,
Listed in Item 17643, Section X. The emulsion or emulsions are usually opposed flat
applied as a continuous layer onto a support with a major surface of
However, this does not necessarily have to be the case. emulsion
Layers are displaced in multiple lateral directions on a flat support surface
Can be applied as a layer segment
Ru. Segment one or more emulsion layers
microcellular supports can be used when
desirable. Useful microcellular supports are internationally
Publication number W080/01614 (published on August 7, 1980)
Opened; Belgian Patent No. 881513, August 1, 1980
) and disclosed in U.S. Patent No. 4,307,165
has been done. The size of the microcell is 1~
200 micrometers, and 1000 mics deep
It can be less than or equal to rom. in general,
In the field of ordinary black and white photography, especially when enlarging photographic images.
In this case, the size of the microcell should be at least 4 mm wide.
micrometers, and 200 micrometers deep
Preferably smaller than the width and width.
The depth is approximately 10 to 100 micrometers.
Ru. Photographic elements employing emulsions according to the invention are not commonly used.
imagewise exposure by any method that
I can do it. Regarding this, please refer to the above research data.
Is Closure, Item 17643, Item X
Please refer. The photosensitive silver halide contained in photographic elements is
Exposure is followed by alkaline media or photographic media.
silver halide in the presence of a developer contained in the base.
by combining with an aqueous alkaline medium
It can be processed according to conventional methods to form a visible image.
can. Once a silver image has been formed in a photographic element, it is
The usual method is to fix silver halide for development.
It is. High aspect ratio tabular grains according to the invention
Emulsion can complete fixation in a shorter time
It is particularly advantageous. The process accelerated by this
theory becomes possible. G. Dye Image Formation Photographic elements and techniques described above for forming silver images.
The method is easy to use to form colored images using dyes.
Can be applied. Possibly projectable colors
The simplest technique for obtaining images is
It is possible to incorporate dyes into the support of a photographic element.
and forming a silver image as described above.
Can be done. In the area where the silver image is formed,
True elements become virtually non-light transparent and other
In the region of , light is transmitted according to the color of the support.
Ru. Colored images can be easily formed in this way.
Ru. This same effect can also be achieved with another dye filter.
- layer or dye filter element and transparent support
This can be achieved by using elements with
can be done. Silver halide photographic elements selectively destroy dyes
or used to form a dye image by forming
can be done. The above-mentioned method for forming a silver image
Photographic elements include research disclosure,
Volume 176, December 1978, Item 17643, X, D
For example, color couplers as described in section
Dye image forming agents such as
-) by using a developer containing
It can be used to form a prime image. this
In such a form, the developer is in oxidized form.
In the state, it reacts with the coupler (coupling)
A color developer capable of forming an image dye (e.g., an aromatic
aromatic primary amines). In some cases, dye-forming couplers are used conventionally.
Therefore, they can also be incorporated into photographic elements. color
Prime forming couplers can achieve different photographic effects.
can be mixed in different amounts to achieve example
For example, the concentration of the coupler in relation to the amount of silver coverage
Amounts commonly used in high-speed and moderate-speed emulsion layers
can be limited lower. Dye-forming couplers are typically used in subtractive color mixing methods.
primary colors (i.e. yellow, magenta and cyan)
selected to form the image dye, which also
These couplers are non-diffusive colorless couplers.
Achieve desired effects in specific photographic applications
reaction in single or multiple separate layers for
Using dye-forming couplers with different response rates
be able to. Dye-forming couplers are
For example, development inhibitors or accelerators, bleach accelerators, etc.
agent, developer, silver halide solvent, toning agent, hardening film
agent, fogging agent, antifogging agent, competitive coupler,
Photos like chemical or spectral sensitizers and desensitizers
can release scientifically useful fragments.
Wear. Development inhibitor releasing DIR couplers are used in the processing field.
It is well known in Furthermore, oxidative cleavage
DIR compounds can also be used. For example,
A compound with relatively poor photosensitivity, such as Tupmann emulsion,
Silver halide emulsions are known for the transfer of development inhibitor fragments.
Prevent or suppress migration
Used as intermediate layer and overcoat layer for
did. Photographic elements form a laminated mask for negative color images
coloring pigments, such as those used to
forming couplers and/or competitive couplers
Can be mixed. Photographic elements are additionally
Can be blended with image dye stabilizers used in
Ru. All of these are included in the Research Discrow.
Jiya, Volume 176, December 1978, Item 117643,
It is described in the section. Inert transition in combination with dye image-forming reducing agent
Using an oxidizing agent in the form of a metal ion complex
By employing the method of forming a dye image or
can be amplified. Photo elements are like that
Particularly suitable for forming dye images by
do. The tabular grain silver halide emulsion of the present invention is
If iodide is present, the amplification reaction, especially the catalyst poison.
Implementation using iodide ions for
can be done. For example, dyes such as silver-dye-bleach method or
By selective destruction of dye precursors
can form a dye image on a photographic element.
Ru. Halo removes developable silver by bleaching.
A technique for forming dye images on silver-genide photographic elements.
This is the normal way to do this. Removal of such silver
processing solutions or bleaching agents in certain layers of the photographic element.
By mixing promoters or their precursors,
can be promoted. In some cases, especially
When amplifying a dye image as described above, development
The amount of silver formed is compared to the amount of dye formed.
There aren't many. Therefore, there is virtually no visible impact.
Silver bleaching is omitted. Furthermore, other applications
In this case, a silver image is retained, and a dye image is
Enhance or supplement the density provided by the image
used for. Enhance the formation of silver images with dyes
If a single neutral dye or an overall neutral painting
Using a combination of multiple dyes that can form an image
is usually desirable. H Partial particle development Certain photodetectors (e.g. video cameras)
etc.) of silver halide photographic elements.
It is possible to show a detection quantum efficiency superior to the detection quantum efficiency.
recognized and reported in the field of photography.
It is. Basics of conventional silver halide photographic elements
As a result of research on the properties of
rather than the low quantum sensitivity of silver oxide grains.
Binary on-off properties of individual silver halide grains
It has been proven that. This means that e.g.
For example, see Shaw, “Multilevel Grading.”
Ins and ideal photograph
Itsuku Detector”, Fotographies
science and engineering,
Volume 16, No. 3, May/June 1972, pp. 192-200
It is described in. Here, silver halide grains
The on-off characteristics of
When the latent image center is formed, the particles can be completely developed.
It means to become capable. Currently, development is a latent image
The amount of light that hits a particle that is greater than the formation limit
It has nothing to do with it. There are many silver halide grains.
Absorb photons and form several latent image centers
or a single one that absorbs only the minimum number of photons
Generate a latent image center or either
Silver halide grains are identical products during development.
occurs. For example, a high aspect ratio flat plate according to the present invention
In the case of a grain emulsion, when it is exposed to light, the emulsion
A latent image center forms in and on the silver halide grains of the agent.
will be accomplished. Some particles have a single latent image center.
However, some particles have many
A latent image center is formed, and some particles also have a shape.
Not done. However, in the latent image formed
The number of hearts is related to the amount of radiation exposure. tabular grain
Since the diameter is relatively large, the sensitivity-grain
(in particular, virtually optimal chemical effects)
In grains formed from silver bromoiodide that can be spectrally sensitized,
(remarkable), their sensitivity is relatively high.
stomach. Number of latent image centers in or on each particle
is directly related to the amount of exposure the particles received.
to ensure that such information is not lost during processing.
Potential for high detection quantum efficiency, provided that
nsial exists. In one preferred form, each latent image
The center is developed to completely remove the silver halide grains.
The size of the latent image center increases without development.
Ru. This is usually done at an earlier stage than usual.
in photographic applications to achieve optimal development.
Prevent silver halide development long in advance
This can be done by other techniques
Techniques using DIR couplers and color developers
There is. Taking advantage of the inhibitor released during coupling
to prevent complete development of the silver halide grains.
can be done. Another way to carry out this process
In this method, a self-suppressing developer is used.
Self-suppressing developers are used to develop silver halide grains.
begins, but the silver halide grains are not fully developed.
It stops the development itself before it is processed.
Ru. A preferred developer of this type is Neuver
Neuberger et al., “Anomalous Con
Centration Effect: An Inba
Earth Relationship Between
The Rate of Development Anne
developer concentration o
Bu Sam p-phenylenediamine”, Huoto
Graphics Science and Engineering
Alling, Volume 19, Volume 19, Issue 6, November 1975-
p-file as described in December, pp. 327-332.
A self-suppressing developer containing enylenediamine.
Ru. Interrupt development or in the presence of DIR coupler
By performing development on the adjacent developer particles,
Silver halide grains with a longer development induction period
development can be completely prevented. However,
However, when using a self-suppressing developer, individual particles
Until after the development of the child has occurred to a certain extent, the development
There are unrestrained advantages. Furthermore, epitaxy
Developability of silver salt and host tabular grains due to yarn growth
Based on the difference from that of silver halide that forms
to obtain or compensate for partial grain development.
It is recognized that we can help.
U.S. Patent No. 4,094,684 describes the developer and development conditions.
Techniques for achieving partial particle developers through the selection of
Discloses the law. Accelerating the development of the latent image center produces many silver nuclei.
to be accomplished. The size and number of these silver nuclei are
is proportional to the degree of exposure of the particles. preferred self
As long as the self-limiting developer contains a color developer, no
The oxidized developer is reacted with the dye-forming coupler.
Accordingly, a dye image can be formed.
However, only a limited amount of halogenation
This way the silver is only developed.
The amount of dye that can be formed is also limited. mosquito
Achieve maximum dye density formation by eliminating such limitations
However, the dye concentration relative to the degree of exposure
As a technique to ensure the proportional productivity of
peroxides or transition metals as oxidizing agents
Using ionic complexes, and also using e.g. color developers.
Silver catalytic oxidation using dye image-forming reducing agents such as
-There are techniques to perform reduction reactions. silver halide grains
If a surface latent image center is formed on the child, this
The center itself catalyzes the dye image amplification reaction.
provide enough silver to Therefore, development
Although the process of promoting the latent image by
Sushi is also not required. In a preferred form
is considered a standard method in color photography.
so that the dye remains in the photographic element after forming the image
Any visible silver that appears is removed by bleaching. The resulting photographic image is directly proportional to the amount of radiation exposure.
Indicates the point-to-point dye density.
It is a dye image. As a result, the detection quantum of photographic elements
The efficiency is very high. Redox reaction as mentioned above
The level of graininess can be increased by
Photographic sensitivity can be easily obtained. International publication number W080/01614 that can be cited first
using a microcellular support as taught in
graininess can be reduced by
Ru. The sense of graininess is the size of individual image dye clouds.
but also by the randomness of their positions.
produced. Supports can form regular arrays
Apply the emulsion to the microcells that
Apply the dye throughout each microcell.
By applying it evenly, you can reduce the graininess.
Sensation can be reduced. Particularly referring to the formation of dye images, the above describes partial grain
Although we have explained secondary development, this does not apply to the formation of silver images.
It can be applied in the same way. Particles containing latent image parts
To complete development before it is completely developed
Development of silver images to see the graininess of silver images
Generation at the image stage can be reduced.
Compared to whole grain development, partial grain development
For example, a larger number of silver centers or nuclei (specks)
The graininess at a given concentration can be reduced by
It can reduce the sense of awareness. Also, coupler
Even in the case of dye image formation performed by blending,
The amount of coupler normally used for silver halide
Concentrate the coupler so that it is less than the stoichiometric amount.
Similarly reduces graininess by limiting the degree of
can be achieved. The amount of silver coverage in a photographic element is
The percentage of partial grain development compared to the percentage of whole grain development.
initially to achieve maximum concentration levels.
Must be larger but not developed
Silver halide is removed by fixation and recovery.
Therefore, the net consumption of silver must be
It doesn't increase either. Silver in photographic elements with microcellular supports
Employing partial grain development in image formation
In the same way as described above regarding dye image formation,
Graininess of silver images can be reduced. example
For example, a silver halide emulsion according to the present invention is deposited on a support.
placed in microcells arranged in
If partially developed after light, it will be accepted upon exposure.
It is proportional to the radiation dose and the number of latent image areas formed.
As a result, many fine silver nuclei are formed. silver core power
Burling power is achieved by whole grain development.
Although it is smaller than when using undeveloped halogen
Fix and remove silver oxides present in microcells
Re-halogenating the silver and then into the microcell
Silver is deposited onto a uniform coating layer of contained physical development nuclei.
Covering by physical development
Power can be increased. on the minute nucleus
Physically developed silver is chemically developed silver
can have a considerably higher concentration compared to
so that fairly high maximum concentrations can be easily obtained.
can. Additionally, physically developed silver is
generated at a uniform concentration in each microcell.
Ru. This reduces graininess. because
For example, the random occurrence of silver concentration
This is because it replaces the regularity of turns. I Sensitivity as a function of spectral region Selecting high aspect ratio tabular grain emulsions of the present invention
within the defined spectral region as described above.
sensitizes the milk within that spectral region.
The sensitivity of an emulsion is determined by its halide composition.
is expected to have inherent sensitivity due to
When compared with the normal spectral range,
much more than previously observed in emulsions.
It is recognized that there are large sensitivity differences.
Ta. In the case of silver bromide and silver bromoiodide emulsions, their
Improper separation in blue and green or red sensitivity of emulsion
Being true has long been a feature of multicolor photography.
It was considered a shortcoming. According to the present invention, the odor
Taking advantage of the difference in spectral sensitivity between silver oxide and silver bromoiodide emulsions
However, this point will be specifically explained below.
will be described with reference to multicolor photographic elements. However, this
The description only serves as an example of its use.
Please note that. guided by the present invention
The increase in spectral sensitivity difference in multicolor photography
Also limited to silver bromide or silver bromoiodide emulsions
It is not something that will be done. Spectral sensitivity of the emulsion of the present invention
Differences observed in photographic elements consisting of a single emulsion layer
I can understand that it is possible. example
For example, in the case of silver chloride and silver chloride emulsions, the
These emulsions have a natural blue sensitivity.
to record green or red light using in multicolor photography
and if so, from blue light exposure
It is known that there is no need for protection.
However, there are differences between various spectral regions.
The advantage of increased sensitivity difference in
It exists in its intended use. For example,
ct ratio tabular grain silver chloride emulsion to infrared radiation
sensitization and imagewise exposure in the spectral sensitization region
a smaller increase in the minimum concentration if
Processing can be performed under light irradiation simply by
Wear. This is because the emulsion according to the invention has a spectral
Sensitivity in the spectral region that does not include sensitization
This is because there is a decline. J Multicolor Photography This invention describes the use of
I can do it. Generally at least one halogen
Any conventional polychrome image containing a silver emulsion layer
The forming element is also a high aspect ratio flat plate according to the present invention.
Adding or substituting a shaped grain emulsion
It can be improved only by The present invention is additive
Multicolor image formation method by method and multicolor image formation method by subtractive method
It can be applied to any law. First, regarding the application of the present invention to additive multicolor image formation.
To explain, the present invention that can form a silver image
can be inserted in combination with photographic elements containing emulsions.
A filter containing blue, green and red filter elements.
Ilter arrays can be used. punk
Romantically sensitized and one of the photographic elements
High aspect ratio flat plate according to the invention forming layers
Additive primary color filter array is applied to the grain emulsion.
Imagewise exposure is performed through the image. Process to form a silver image
See through the filter array
A multicolored image can be seen. project an image like this
It is best seen when Therefore, photographic elements and
All filter arrays have transparent supports
or share. Multicolor by combination of subtractive primary color image forming dyes
Application of the present invention to multicolor photographic elements in image-forming format
It can also bring special benefits by using
can. Such photographic elements include a support as well as
Typically blue, green and red exposures respectively
Separately as yellow, magenta and cyan dye images
Record at least 3 sets of overlapping halogens
It consists of a silver emulsion layer. The present invention generally
High aspect ratio tabular grain halogen
Any multicolor photographic element of this type containing a silver oxide emulsion
including high aspect ratio tabular grain odors.
Further, when silver oxide and silver bromoiodide are used,
benefits are brought about. Therefore, silver bromide and
Regarding preferred embodiments in which silver bromoiodide emulsion is mixed
As explained below, any halide group
High aspect ratio tabular grain emulsions with
It can be used as desired. Not specifically stated
As far as multicolor photographic elements are concerned, the above-mentioned characteristics of photographic elements are
You can have it. In one particularly preferred form of the invention, the micro
Eggplant blue sensitized high aspect ratio tabular grain odor
Silver oxide or silver bromoiodide emulsions are three types of multicolor photographic elements.
A set of blue, green and red recording emulsion layers with green in them
or at least one of the emulsion layers to record red light.
Forming two. This tabular grain emulsion is
During the exposure stage of the true element, the
In addition to the light that is present, 5500〓neutral light in blue light
will be arranged to receive. This emulsion layer
The relationship between blue and negative blue light is ΔlogE
It can be expressed as ΔlogE=logE _T −logE _B In the above equation, E _T is recorded by tabular grain emulsions.
The logarithm of the amount of exposure to green or red light that should be
Yes, also logE _B The tabular grain emulsion is
is the logarithm of the amount of exposure to blue light received by
In either case, unless otherwise specified, the exposure amount E is
It is expressed in meters-candle-seconds. In the practice of the invention, ΔlogE is less than 0.7
(preferably less than 0.3), which
Yet still obtain an acceptable reproduction of a multicolored object
be able to. This is the average straightness used in the present invention.
in emulsions with diameters greater than 0.7 micrometers.
This is surprising given the high proportion of emulsion grains present.
It is the right thing to do. If the high surface area used in the present invention
Pect ratio tabular grain silver bromide or silver bromoiodide emulsions
Similar halide composition and average grain
an equal amount of non-tabular or low apertures with child diameters
If a spectral tabular grain emulsion is used,
of color that is higher and usually exceeds acceptable limit levels.
This will cause distortion. green or red sensitized
Color distortion caused by silver bromide and silver bromoiodide emulsions
can be reduced by reducing the average particle diameter.
It is known in the photographic field that
However, the maximum image density that can be achieved by decreasing the particle diameter
True sensitivity is limited. The invention is blue and minus
It not only advantageously separates the blue sensitivity, but also achieves
Maximum achievable minus no effect on blue photographic sensitivity
Achieve such benefits without any adverse effects.
In particularly preferred forms of the invention, at least
The minus blue recording emulsion layer is made of silver bromide according to the present invention.
Or composed of silver bromoiodide emulsion. triple emulsion layer
The blue recording emulsion layer therein is also advantageously according to the invention.
Consisting of high aspect ratio tabular grain emulsions
Can be done. In a particularly preferred form of the invention
is the thickness present in each of the triple emulsion layers
Few tabular grains less than 0.3 micrometers
1.0 micrometers, preferably at least
also has an average particle diameter of 2.0 micrometers
Ru. In yet another preferred embodiment of the invention
The multicolor photographic element must have an ISO sensitivity of at least 180.
can have a number. A multicolor photographic element having an emulsion according to the invention comprises:
High aspect ratio tabular grains green and (also
) to protect the red emulsion layer from blue light exposure
A yellow filter layer is placed between these layers and the exposure source.
There is no need to place
Even if a filter layer is placed, no daylight exposure is required.
The red or green recording emulsion layer of a photographic element is
Traditionally used to protect against exposure to light
Reduce the concentration to lower than the yellow filter layer concentration
be able to. One particularly preferred form of the invention
Now, of the three emulsion layers, green and (also
) between the red recording emulsion layer and the exposing radiation source;
No intervening color recording emulsion layer. Therefore, the photo
The elements are incident with green and/or red emulsion layers
Having a substantially blue-absorbing material between it and the exposing radiation
Not worth it. One green or red record high aperture as described above.
Spectral ratio tabular grain silver bromide or silver bromoiodide milk
Multicolor photographic elements are
for exposure to blue, green and red light respectively.
Contains at least three separate emulsion layers.
High aspect ratio tabular grain green or
Emulsions other than the red recording emulsion layer are of any conventional type.
It may be of any format. various commonly used
Emulsions can be cited in Research Disclosure
Y., Item 17643, Section I.
Ru. All emulsion layers are silver bromide or silver bromoiodide.
Preferably, it includes plate-like host particles. Especially preferred
At least one green record in the new form
The emulsion layer and at least one red recording emulsion layer are
High aspect ratio tabular grain emulsions of the invention
Ru. If the spectrum is green and/or
Two or more emulsion layers are placed to record the red part
If so, at least the high speed emulsion layer should be
It is desirable to incorporate a spectral ratio tabular grain emulsion.
Delicious. Of course all the blue color of the photo elements,
Green and red recording emulsion layers described above as required
According to the present invention, it is composed of tabular grains of
It turns out that this is not essential, but preferred. The present invention has a wide range of sensitivity and contrast characteristics.
Blue, green and red recording emulsion layers showing
It is fully applicable to multicolor photographic elements with.
Spectrally sensitized to green or red used in the present invention
High aspect ratio tabular grain silver bromide or bromoiodide
The silver emulsion layer is relatively insensitive to blue, so
The green and/or red recording emulsion layers are
color within a multicolor photographic element, regardless of the emulsion layer.
You can also place them in
Conventionally, precautions have been taken to prevent exposure to blue light.
There's no need to pay attention. The present invention particularly provides accurate color reproduction by daylight exposure.
It can be applied to multicolor photographic elements to be reproduced. This way
Eel type photographic elements should be placed on a 5500〓 (daylight) source.
Virtually comparable contrast and control when exposed to light
Blue, green and red with limited sensitivity changes
It has the characteristic of forming a record of light. here
In, the term "substantially comparable contrast" and
The contrast of blue, green and red records
20 based on the contrast of the blue record.
less than % (preferably less than 10%) different
means. Limited blue, green and red records
Sensitivity change is less than 0.3logE
(ΔlogE) (where,
Sensitivity changes are the sensitivity of green and red records and the sensitivity of blue records.
Indicates the larger of the two differences with the sensitivity of the color record.
vinegar). Determining the above relationships of photographic elements according to the invention
Measuring the contrast and log sensitivity required for
At a color temperature of 5500〓, the photographic element is
Spectrally non-selective (neutral density) like the raw test subject
exposure through a step wedge, preferably
photographic elements under the processing conditions available for use.
This can be done by processing. Amelie
Can Standard PH2.1−1952 (American
National Standards Institute
"ANSI", 1430 Broadway, New York
The wave as described in
Blue light with a wavelength of 435.8 nm, green light with a wavelength of 546.1 nm, and
and photos for transmission of red light with a wavelength of 643.8nm
Measuring the blue, green and red density of elements
and the blue, green, and red characteristics of photographic elements.
The sex curve can be plotted. if photo
The element has a reflective support rather than a transparent support
If so, use reflection density instead of transmission density.
I can do it. Blue, green and red characteristic curves?
sensitivity and contrast in the photographic field.
This can be verified using well-known techniques.
Each blue, green and red record is a comparison target.
specific to be adopted as long as it is similarly measured for the purpose of
The sensitivity and contrast measurement method itself is important.
It's not important. Used for different photographic applications
Standard sensitometric measurements of various types of multicolor photographic elements
A standard technique is published by ANSI. representative
Publications such as American Standard
PH2.21−1979, PH2.47−1979 and PH2.27−
It was 1979. The present invention enables accurate color reproduction during daylight exposure.
Multicolor photographic elements using such emulsions have the above-mentioned properties.
shows considerable advantages over traditional photographic elements.
have In the photographic element according to the invention, green
and tabular silver bromide or red spectrally sensitized
Depends on the limited blue sensitivity of the silver bromoiodide emulsion layer
The blue sensitivity of the blue recording emulsion layer and the negative blue
It is possible to separate the blue sensitivity of the recording emulsion layer.
Ru. Green and red depending on the specific application field
Utilization of tabular grains in the recording emulsion layer itself
of the blue and minus blue recording emulsion layers by
produce the desired amount of separation in the blue response.
You can In some applications, commonly used blue sensitivity separation
Blue and minus blue recording emulsions using techniques
The blue sensitivity separation of the layer is further improved, resulting in a high aspect ratio.
Blue color obtained due to the presence of tabular grains
It is desirable to compensate for degree separation. For example, the most sensitive
The green recording emulsion layer with high intensity is the best choice for the exposure radiation source.
The blue color has the highest sensitivity and is located close to the
Place the recording emulsion layer furthest from the exposing radiation source.
If arranged, the blue and green recording emulsion layers
Separation of blue sensitivity is done by applying the emulsion separately and
Complete order size if exposed to light
Although "1.0logE" is different) such a layer arrangement configuration
can be effectively reduced by Why
In contrast, the green recording emulsion layer loses all blue color during exposure.
Accepts light, but green recording emulsion layer and other
The upper layer of the blue light before it reaches the blue recording emulsion layer
This is because some of it is absorbed or reflected. child
In such cases, high iodide content is added to the blue recording emulsion layer.
By blending in this proportion, tabular grains can be colored blue.
Color and minus blue sensitivity of blue recording emulsion layer
This can compensate for the increase in distance. Blue recording emulsion layer
is minus the blue recording emulsion layer than the exposed radiation source
blue and negative if placed close to
Limited density coated between blue recording emulsion layers
Utilizing yellow filter material, blue and magenta
blue color separation can be increased. deer
However, the conventional sensitivity separation technique itself has low blue sensitivity.
The difference in magnitude in the separation or a value that approximates it
Until now, in the field of photographic technology,
Traditional sensitivity separation techniques as required
It is not necessary to use . But long
For certain fields of use, abnormally large blue and
and minus blue sensitivity separation is desired.
The above shall not be excluded. Therefore, according to the present invention,
The multicolored photographic element has a balanced lightness.
Accurate image color when exposed under lighting conditions
It is possible to reproduce the
Composition of photographic elements goes beyond what was previously possible.
This greatly expands the range of choices that can be made.
Ru. Multicolor photographic elements often contain color-forming layer units.
will be explained. The most common multicolor photo required
The element contains three overlapping chromogenic layer units.
Each chromogenic layer unit has a spectral
can record different 1/3 of colors and complementary colors
at least one pigment capable of producing a subtractive primary dye image;
Contains a silver halide emulsion layer. That is, blue, green and
The yellow and red recording color forming layer units are yellow and red, respectively.
Used to produce magenta and cyan dye images.
I can stay. Dye image-forming substances are not necessarily
It does not have to be present in the color forming layer unit.
can be supplied entirely from the processing solution.
In providing dye image-forming substances in photographic elements
can also be placed in an emulsion layer or
Oxidation from adjacent emulsion layers in the same color-forming layer unit
positioned to receive a developing or electron transfer agent.
can be arranged in layers. A developer that oxidizes between color forming layer units or
Prevents color deterioration due to migration of electron transfer agents
Scavengers are commonly used to
Ru. Scavenger U.S. Patent No. 2937086
within the emulsion layer itself (or
) as described in U.S. Patent No. 2,336,327
Placed in the intermediate layer between adjacent color forming layer units
can do. Each color forming layer unit contains a single emulsion layer.
A single chromogenic layer unit
Often 2, 3 or more photographic sensitivities in
Different emulsion layers are provided. desired layer structure
Multiple emulsion layers with different sensitivities are combined into a single color-developing layer.
If you do not allow placement in a single photo
Multiple (usually 2 or 3) blue, green colors in an element
and/or a red recording chromogenic layer unit.
Generally, it is provided. Tabular silver bromide or
at least one green color containing silver bromoiodide grains or
Placing a red recording emulsion layer and imagewise exposure of the photographic element
What causes us to accept an increased proportion of blue light is
One Unique Feature of Photographic Elements Having Emulsions of the Invention
It is. High aspect for increased proportion of blue light
To reach the tabular grain emulsion layer,
Absorption of blue light by the yellow filter layer placed
or preferably yellow on top.
No filter layer is provided at all. Ma
In addition, a color forming layer containing a high aspect ratio tabular emulsion
By placing the unit close to the exposure radiation source
High aspect ratio increases the proportion of blue light
It is possible to reach the tabular emulsion layer.
Ru. For example, green and red record high aspect
green and red containing tabular grain emulsions, respectively
The color recording color forming layer unit is replaced with the blue recording color forming layer unit.
be placed closer to the exposure radiation source than the nits.
Can be done. The multicolor photographic element according to the invention meets the above requirements.
Any form commonly used as long as it satisfies
good. Gorokhovskii, Sp.
Kutle Studies of the Photography
Itsuku Process, Focal Press, New
Six possibilities listed in York, p.211, table 27a
Any layer configuration can be adopted. Simple and
To explain clearly, the commonly used multicolored halo
During the preparation of silver-genide photographic elements, such
photographic elements, the negative blue part of the spectrum
sensitized and exposed prior to other emulsion layers.
one or more placed in the line of fire
Providing a high aspect ratio tabular grain emulsion layer
Can be done. However, in most cases it is necessary
In addition to changing the layer structure accordingly, the conventional minus
Blue recording emulsion layer with one or more high aspect ratios
Ratio of tabular grains minus blue recording emulsion layer
It is desirable to change it. Layer composition preferred below
The present invention can be more fully understood from these
will be able to understand.

【table】

【table】

[Table] In the above layer structure, B, G and R represent conventional types of blue, green and red recording color forming layer units, respectively; , represents one or more emulsion layers comprising a high aspect ratio tabular grain silver bromide or silver bromoiodide emulsion as specifically described above; R represents that the photographic sensitivity of the color-forming layer unit is greater than the sensitivity of at least one other color-forming layer unit recording exposures in the same 1/3 of the spectrum in the same layer configuration; S written before B, G or R means that the photographic sensitivity of the color forming layer unit is the same 1/3 of the spectrum of the same layer structure.
IL represents an intermediate layer containing scavenger but substantially free of yellow filter material. Each fast or slow chromogenic layer unit has the same one-third of the spectrum as a result of its position in the layer configuration, its inherent sensitivity characteristics, or both.
It can have a different photographic sensitivity than other color-forming layer units that record exposures. In the layer structure shown in I~, the position of the support is not shown. According to common law, in most cases,
The support will be positioned furthest from the exposing radiation source, ie at the bottom of each layer arrangement. If the support is colorless and specular, ie transparent, the support can be placed between the exposure source and the described arrangement. More generally, the support can be placed between the exposure source and any color-forming layer unit in which the light transmitted by the support is to be recorded. Returning now to layer configuration I, this photographic element is substantially free of yellow filter material. However, according to the prior art for elements containing yellow filter material, the blue recording color forming layer unit is located closest to the source of exposing radiation. In simple form, each color forming layer unit consists of a single silver halide emulsion layer. In another form, two, three or more different silver halide emulsion layers can be combined into each color forming layer unit. When comparing three sets of emulsion layers, one of which has the highest sensitivity, it is desirable that their contrast be substantially comparable, and that the photographic speed of the green and red recording emulsion layers is as high as that of the blue recording emulsion layer. Desirably differs from sensitivity by less than 0.3 logE. If two, three or more different emulsion layers with different sensitivities are present in each color-forming layer unit, two, three or more emulsion layers in the triplet in layer configuration I with a given contrast and speed relationship It is desirable that there be at least one. The absence of yellow filter material directly beneath the blue recording color forming layer unit increases the photographic sensitivity of the blue recording color forming layer unit. It is not essential that the intermediate layer in layer configuration I is substantially free of yellow filter material. Less than the amount commonly used of yellow filter material may be placed between the blue and green recording color forming layer units without departing from the teachings of this invention. Additionally, less than the amount commonly used of yellow filter material may be included in the intermediate layer separating the green and red recording color forming layer units without departing from the invention. When using a conventional amount of yellow filter material, the red recording color forming layer unit is not limited to the above-mentioned tabular silver bromide or silver bromoiodide grains, but may be any conventional one, as long as contrast and sensitivity are considered. Any form can be adopted. In order to avoid duplication, only the features that distinguish layer configurations ~ and layer configuration I will be specifically described. The layer configuration provides two separate blue, green and red recording color layer units, rather than mixed fast and slow blue, red or green recording emulsion layers in the same color layer unit. High sensitivity coloring layer unit 1
or only two or more emulsion layers must contain the aforementioned tabular silver bromide or silver bromoiodide grains. The low-sensitivity green and red recording color-forming layer units, combined with their low sensitivity and the fact that the high-sensitivity blue recording color-forming layer unit is placed on top, allow blue light exposure without the use of yellow filter material. be adequately protected from Of course, this does not preclude the use of high aspect ratio tabular grain silver bromide or silver bromoiodide emulsions in one or more emulsion layers of the slow green and/or red recording color forming layer unit. When the high-sensitivity red recording color-forming layer unit is placed on top of the low-sensitivity green recording color-forming layer unit,
4184876 and German Patent Publication no.
Increased sensitivity is achieved as taught in US Pat. The layer structure differs from layer structure I in that the blue recording color forming layer unit is disposed farthest from the exposure source. Therefore, the green recording color forming layer unit is located closest to the light source, and the red recording color forming layer unit is located relatively close to the light source.
This layer structure is advantageous for forming a high-quality multicolor image with high sharpness. This green color recording layer unit, which makes the most important visual contribution to the formation of a polychromatic image, is located closest to the exposure source and no light-scattering upper layer is formed on top of it. Chromogenic layer units can form very sharp images. The red recording chromophoric layer unit, which makes the next most important visual contribution to the formation of a polychromatic image, receives light that passes only through the green recording chromophoric layer unit and is therefore not scattered into the blue recording chromophoric layer unit. do. Although the blue recording color-forming layer unit suffers compared to layer configuration I, the loss in sharpness does not offset the advantages of the green and red recording color-forming layer units. This is because the visual contribution of the blue recording color forming layer unit to the polychromatic image is not very important. The layer structure is an extension of the layer structure to provide green and red recording color forming layer units containing separate high speed and low speed high aspect ratio tabular grain emulsions. Layer configuration V
This differs from the layer structure in that an additional blue recording color forming layer unit is provided on the low-sensitivity green, red and blue recording color forming layer units. The high aspect ratio tabular grain silver bromide or silver bromoiodide emulsion described above is used in the high sensitivity blue recording color forming layer unit. In this case, since this high-sensitivity blue recording color-forming layer unit absorbs blue light, the proportion of blue light reaching the low-sensitivity green and red recording color-forming layer units is reduced. In a variant, it is not necessary to use high aspect ratio tabular grain emulsions in the slow green and red recording color forming layer units. The layer configuration differs from the layer configuration in that a tabular grain blue recording color forming layer unit is disposed between the green and red recording color forming layer units and the exposing radiation source. As already pointed out,
A tabular grain blue recording color-forming layer unit can be comprised of one or more tabular grain blue recording emulsion layers, and if multiple blue recording emulsion layers are present, the sensitivities can differ. In the layer structure, unlike the layer structure, in order to compensate for the disadvantages suffered by the red recording color forming layer unit, a second high-sensitivity red recording color forming layer is provided between the tabular grain blue recording color forming layer unit and the exposure radiation source. The gender unit is located. Since this second tabular grain high-sensitivity red recording color-forming layer unit is arranged at a favorable position, if the same emulsion is used in the two units, the sensitivity of the second high-sensitivity red recording layer unit will be the highest. 1 high sensitivity red recording layer unit. Of course, these first and second high speed tabular grain red recording color forming layer units can be constructed of the same or different emulsions as desired, and their relative sensitivities can be determined according to techniques well known in the photographic art. It can therefore be adjusted.
Instead of using two high-sensitivity red recording layer units as described above, the second high-sensitivity red recording layer unit can be replaced by a second high-sensitivity green recording color forming layer unit, if desired. The layer structure may be the same as that of the layer structure, but the second high-sensitivity tabular grain red recording color-forming layer unit and the second high-sensitivity tabular grain green recording color-forming layer unit are connected to the exposing radiation source and the tabular grain layer unit. The difference is that the particles are interposed between the blue recording color forming layer units. Of course, the above-mentioned layer configurations I~ are merely examples and there are many other advantageous layer configurations. In each of the various layer configurations, the corresponding green and red recording color forming layer units can be rearranged, i.e. the sensitive red and green recording color forming layer units can be rearranged in the various layer configurations. Additionally or alternatively, the low speed green and red recording chromophoric layer units can be rearranged. Photographic emulsions that form multicolor images consisting of a combination of multiple subtractive primary color dyes usually take the form of polymerizing multiple layers containing dye-forming materials such as dye-forming couplers, but this is not always necessary. isn't it. 1/1 of the visible spectrum, respectively
3 color-forming components (commonly called packets), including a silver halide emulsion for recording 3 and a coupler capable of forming complementary subtractive primary color dyes.
can be placed together in a single layer in a photographic element to form a multicolor image. Representative mixed packet multicolor photographic elements are described in US Pat. No. 2,698,794 and US Pat. No. 2,843,489. The relatively large separation of blue and minus blue sensitivities of green and red recording color forming layer units containing tabular grain silver bromide or silver bromoiodide emulsions allows for the elimination or reduction of yellow filter material and/or the creation of new layers. configuration can be adopted.
One technique that makes it possible to quantitatively measure the relative response of the green and red recording chromogenic layer units to blue light in a multicolor photographic element is to first pass a sample of the multicolor photographic element according to the invention through a step tablet to a neutral state. The first step is to expose the sample to an exposure source (ie, 5500 〓 of light) and then process the sample. A second sample is then exposed in the same manner. However, exposure is performed without intervening a Wratten 98 filter that transmits only light between 400 nm and 490 nm, and then the same process is performed. Three dye characteristic curves can be plotted for each sample using the blue, green and red transmission densities determined according to American Standard PH2.1-1952 as described above. The difference between the blue sensitivity of the blue recording color forming layer unit and the blue sensitivity of the green or red recording color forming layer unit can be determined from the following relational expression. (A) Δ=(B _W98 −G _W98 )−(B _N −G _N ) or (B) Δ=(B _W98 −R _W98 )−(B _N −R _N ) In the above formula, B _W98 is Ratsuten98 G _W98 is the blue sensitivity of the blue recording color forming layer unit exposed through a Wratten 98 filter; R _W98 is the blue sensitivity of the green recording color forming layer unit exposed through a Wratten 98 filter; BN is the blue sensitivity of the layer unit; _BN is the blue sensitivity of the blue recording layer unit exposed to neutral (5500〓) light; G _N is the green recording chromogenic layer unit exposed to neutral (5500〓) light. is the green sensitivity of the layer unit; R _N is the red sensitivity of the red recording color forming layer unit exposed to neutral (5500〓) light. In the above description, blue, green and red densities have been expressed based on blue, green and red recording chromophoric layer units, ignoring undesirable spectral absorption by yellow, magenta and cyan dyes. Such undesirable spectral absorptions are unlikely to be of sufficient magnitude to substantially influence the results obtained here for the purposes of the present invention. Multicolor photographic elements employing emulsions according to the present invention can achieve at least the blue sensitivity of a green and/or red recording color forming layer unit containing a high aspect ratio tabular grain emulsion as described above without the presence of a yellow filter material. 6 times, preferably at least 8
and more preferably at least 10 times the blue sensitivity due to the blue recording color forming layer unit. Another technique for measuring the large separation in blue and minus blue sensitivities of multicolor photographic elements according to the invention is to compare the green sensitivity of a green recording chromophoric layer unit or the red sensitivity of a red recording chromophoric layer unit to its blue sensitivity. That's true. The same exposure and processing techniques as above are used. however,
Neutral light exposure is replaced by negative blue light exposure by interposing a Wratten 9 filter that transmits only light above 450 nm. The quantitative differences Δ″ and Δ are expressed by the following formula: (C) Δ″=G _W9 −G _W98 or (D) Δ=R _W9 −R _W98 In the above equation, G _W98 and R _W98 are defined as before. G _W9 is the green sensitivity of the green recording chromophoric layer unit exposed through the Wratten 9 filter; and R _W9 is the red sensitivity of the red recording chromophoric layer unit exposed through the Wratten 9 filter. Again, undesired spectral absorption by the dye is not important and will be ignored. Red and green recording color forming layer units containing tabular silver bromide or silver bromoiodide emulsions as described above have a sensitivity between the sensitivity in the blue region of the spectrum and the part of the spectrum that is spectrally sensitized (i.e. between blue and minus blue sensitivity). difference) of at least 10 times (1.0 logE), preferably at least 20 times (1.3 logE). The quantitative relationships A:B and C:D for the same elements will not result in identical results (except for the wavelength of spectral sensitization) even if the green and red recording color forming layer units are identical. The reason for this is that in most cases the red recording color forming layer unit receives light that has already passed through the corresponding green recording color forming layer unit. However, if a second element is provided that is identical to the first element except that the positions of the corresponding green and red recording color forming layer units have been changed, the red recording color forming layer of this second element The green recording color forming layer unit of the first element is A.
Substantially the same value shown for the relationship between and C should be shown for the relationship between B and D. In short, simply choosing green spectral sensitization as opposed to red spectral sensitization does not significantly affect the numbers obtained by the quantitative comparisons described above. Therefore, it is common practice to treat blue and red sensitivities as relatively negative blue sensitivities, without distinguishing between green and red sensitivities compared to blue sensitivities. F. Reduced High Angle Scattering The high aspect ratio tabular grain emulsions of the present invention are superior to nontabular grains and low aspect ratio tabular grain emulsions in that they exhibit reduced high angle light scattering. This can be shown quantitatively. In FIG. 4, a sample of Emulsion 1 is coated onto a transparent (specular) support 3 at a silver coverage of 1.08 g/m ² . Although not shown in the figures, it is desirable that the emulsion and support be immersed in liquids having substantially matched refractive indices to minimize Fresnel reflections at the emulsion and support surfaces. The emulsion coating is exposed to light by a parallel light source 5 from a direction perpendicular to the surface of the support. The light from the light source impinges on the emulsion coating at point A through a light path forming an optical axis indicated by dotted line 7. Light transmitted through the support and emulsion can be detected at a hemispherical sensing surface 9 placed at a distance from the emulsion. The maximum intensity level of light is detected at point B, which corresponds to the intersection of the first optical path extension and the sensing surface. In FIG. 4, an arbitrarily chosen point C on the sensing surface is shown. The dotted line connecting AC makes an angle φ with the emulsion coating. By moving point C on the sensing surface, φ can be varied in the range 0-90°. By measuring the intensity of the scattered light as a function of the angle φ, it is possible to measure the cumulative light distribution as a function of the angle φ (because of the rotational symmetry of the light scattering around the optical axis 7). . For a background discussion of cumulative light distribution, see Depalma and Gasper, Determining the Optical Properties of Photographic Emulsions by the Monte Carlo Method. , Photographic Science and Engineering, Volume 16, No.
3, May-June 1971, pp181-191. After measuring the cumulative light distribution as a function of the angle φ in the range 0 to 90° for emulsion 1 according to the invention, a conventional emulsion with the same average grain volume and the same silver coverage on another part of the support 3 was measured. and repeat the above procedure. In comparing the cumulative light distribution as a function of the angle φ for these two emulsions, it is found that for values of φ up to 70° (in some cases up to 80° or more), the scattered light of the emulsion according to the invention The amount of is small. In FIG. 4, the angle θ is shown as a complementary angle to the angle φ. The scattering angle will be described here as an angle θ. Therefore, the high aspect ratio tabular grain emulsions of this invention exhibit less high angle scattering. Since high angle light scattering severely reduces image sharpness, the high aspect ratio tabular grain emulsions of this invention can form images with excellent sharpness in either case. As used herein, the term "collection angle" means that half of the light impinging on the sensing surface lies within the area corresponding to the cone formed by the line AC rotating around the polar axis at an angle θ. , which refers to the value of the angle θ when half of the light that hits the sensing surface hits the sensing surface within the remaining area. While not wishing to be limited by reasoning that the high aspect ratio tabular grain emulsions of this invention exhibit reduced high angle scattering, it is important to note that the large, flat major crystal faces of the high aspect ratio tabular grains It is believed that the orientation of particles in the coating film contributes to improving sharpness. It has specifically been observed that the tabular grains present in the silver halide emulsion coating are substantially aligned on the flat support surface on which they are formed. Thus, light impinging on the emulsion layer from a direction perpendicular to the photographic element impinges substantially perpendicularly to one major crystal face of the tabular grains. The thinness of the tabular grains, combined with their orientation during coating, results in the high aspect ratio tabular grain emulsion layers of this invention being substantially thinner than conventional emulsion coatings, resulting in improved sharpness. will improve. However, the emulsion layer according to the present invention exhibits superior sharpness even when coated to the same thickness as a conventional emulsion layer. In particularly preferred forms of the invention, the high aspect ratio tabular grain emulsion layer is at least 1.0 micrometers, more preferably at least 2
Indicates the minimum average particle diameter in micrometers.
Increasing the average particle diameter improves both sensitivity and sharpness. Although the maximum average grain diameter that is useful will vary depending on the graininess that is acceptable for the particular imaging application, the maximum average grain diameter of high aspect ratio tabular grain emulsions according to the present invention is in any case It is also less than 30 micrometers, preferably less than 15 micrometers, more preferably less than 10 micrometers. Although it is possible to reduce high-angle scattering in single-layer coatings of high aspect ratio tabular grain emulsions according to the present invention, reduction in high-angle scattering is not necessarily achieved as a corollary in multicolor coatings. do not have. Although improved sharpness is achieved in certain multicolor coating configurations using the high aspect ratio tabular grain emulsions of the present invention, in other multicolor coating configurations, the high aspect ratio tabular grain emulsions of the present invention Grain emulsions can actually reduce the sharpness of the underlying emulsion layer. Returning to Layer Configuration I, the blue recording emulsion layer is located closest to the exposing radiation source, while the underlying green recording emulsion layer is comprised of a tabular grain emulsion according to the present invention. Additionally, a green recording emulsion layer is disposed over the red recording emulsion layer. If the green recording emulsion layer contains grains with an average diameter of 0.2 to 0.6 micrometers, as is the case in many non-tabular emulsions, there will be maximum scattering of light passing through it to the green and red recording emulsion layers. will be seen. Unfortunately, if the light is already scattered before it reaches the high aspect ratio tabular grain emulsion that forms the green recording emulsion layer, the tabular grains will prevent the light passing through it to the red recording emulsion layer from the conventional emulsion. can be scattered much more than Therefore, this particular emulsion and layer configuration selection results in a greater reduction in the sharpness of the red recording emulsion layer compared to a layer configuration without emulsion according to the invention. The emulsion layer underlying the high aspect ratio tabular grain emulsion layer according to the invention is designed to receive substantially unscattered (preferably specularly transmitted) light in order to achieve the sharpness object of the invention. It is desirable to arrange the tabular grain emulsion layer in the second layer. In other words, achieving the best sharpness in the emulsion layer underlying the tabular grain emulsion in the photographic elements of this invention is only possible if the tabular grain emulsion layer itself is not located beneath the turbid layer. It will be done. For example, if a high aspect ratio tabular grain green recording emulsion layer is disposed above a red recording emulsion layer and below a Lippmann emulsion layer and/or a high aspect ratio tabular grain blue recording emulsion layer according to the present invention. For example, the sharpness of the red recording emulsion layer may be improved by the presence of one or more tabular grain emulsion layers disposed thereon. Quantitatively, the sharpness of the red recording emulsion layer is improved if the collection angle of one or more layers above the high aspect ratio tabular grain green recording emulsion layer is less than about 10 degrees. Of course, as far as the effect of the overlying layer on sharpness is concerned, it is not important that the red recording emulsion layer itself be a high aspect ratio tabular grain emulsion layer according to the invention. In multicolor photographic elements formed by polymerizing multiple color-forming units, the emulsion layer closest to the exposing radiation source is comprised of at least a high aspect ratio tabular grain emulsion to achieve the sharpness benefits aimed at by the present invention. It is desirable to do so. In a particularly preferred form of the invention, each emulsion layer located closer to the exposing radiation source than the other image-recording emulsion layers is comprised of a high aspect ratio tabular grain emulsion. The foregoing layer configurations, , V, and are illustrative of layer configurations of multicolor photographic elements according to the present invention that can significantly improve the sharpness of the underlying emulsion layers. Although the superior contribution of high aspect ratio tabular grain emulsions to image sharpness in multicolor photographic elements has been discussed in detail with reference to multicolor photographic elements, the sharpness advantage is It is also recognized in black and white photographic elements. It is a common technique to separate emulsions that form black-and-white images into fast and slow layers. The use of the high aspect ratio tabular grain emulsions of this invention in layers close to the exposing radiation source improves the sharpness of the underlying emulsion layers. (4) Embodiments The present invention will be explained in more detail with the following examples. In each instance, the reaction vessel contents were vigorously stirred during each introduction of the silver and halide salts. The term "percentage" means percentage by weight, unless otherwise specified;
The symbol "M" represents molar concentration unless otherwise specified. All solutions are aqueous unless otherwise noted. Average diameter and projected area (%) of tabular grains in emulsions
Tabular grains (less than 0.6 microns in diameter), unless otherwise specified
However, there were tabular grains with small diameters that were insufficient to significantly change the reported values. Comparative Example 1 In this example, tabular grain AgBrI containing 6 mol% iodide and not previously spectrally sensitized was used.
The non-selective epitaxial growth of silver chloride on an emulsion will be explained. Emulsion 1A Tabular AgBrI host grains (6 mol% iodide) 1.5% at 55°C containing 0.12M potassium bromide
A 2.0 mol KBr solution containing 0.12 mol KI and a 2.0 mol AgNO ₃ solution were added to the gelatin solution 6.0 over 8 minutes while stirring it and by double-jet method, and during that time 0.92
maintained pBr (consumed 5.3% of total silver nitrate usage). The bromide and silver salt solutions described above were then introduced simultaneously at an accelerated flow rate (6.0× from start to finish, i.e., the flow rate at the end was 6.0 times greater than that at the start) while maintaining pBr = 0.92. was added over a period of 41 minutes (consuming 94.7% of the total amount of silver nitrate used). A total of 3.0 moles of silver were used. The emulsion was cooled to 35°C, washed by the coagulation method described in US Pat. No. 2,614,929, and stored at 40°C with pAg = 7.6. The resulting tabular grain AgBrI (6 mol% iodide) emulsion was
The average grain diameter of the tabular grains was 3.0 μm, the average thickness was 0.09 μm, the average aspect ratio was 33:1, and 85% of the grains were tabular based on projected area. Emulsion 1B Epitaxial growth of AgCl on the main crystal planes of host grains 0.1 mol of AgNO ₃ solution was added to 40 g of tabular grain AgBrI emulsion 1A (0.04 mol) prepared as above to adjust the pAg at 40°C to 7.2. Adjusted. 1.0ml
A 0.79M NaCl solution was added. Then, while keeping the pAg at 7.5 at 40 °C, 0.54 molar
NaCl and 0.5M AgNO ₃ solution were added in a double jet over 8.3 minutes. 5 of the total amount of silver halide
AgCl in the amount of mol % was obtained as a deposit by epitaxial growth. For simplicity, this emulsion layer will be referred to as the 5 mol% AgCl emulsion, and similar nomenclature will apply to the emulsions below. FIG. 5 is a carbon replica electron micrograph of the emulsion. This photograph shows that silver chloride was deposited on the main crystal faces. The deposits formed are generally more or less random on the main crystal faces, although for some grains epitaxy appears to predominate near the edges of the main crystal faces. Note that no spectral sensitization of the AgBrI (6 mole % iodide) host emulsion was performed prior to the addition of silver chloride. Example 2 This example describes the deposition of AgCl along the grain edges of a spectrally sensitized tabular grain AgBr emulsion. Emulsion 2A Tabular AgBr host grains at 80°C containing 0.073 moles of sodium bromide
Add 0.30 mol NaBr to the 1.5% gelatin solution 2.0 while stirring it and by double jet method.
The solution and 0.05M AgNO ₃ solution were added over 5 minutes, during which time a pBr of 1.14 was maintained (consuming 0.4% of the total silver nitrate usage). Then, the bromide and silver salt solutions described above were added at the same time.
It was added over 4 minutes at an accelerated flow rate (3.0x from start to finish) while maintaining pBr = 1.14 (consuming 0.66% of the amount of silver nitrate used). Then,
A 1.5 molar NaBr solution and a 1.5 molar _AgNO3 solution were added over 25 minutes at an accelerated flow rate (14.3x from start to finish) while maintaining pBr = 1.14 (66.2% of silver nitrate usage). ). Then stop the acceleration, and let the solution flow at a constant flow rate of 6.6
(32.8 of the amount of silver nitrate used)
%). In total, about 3.03 moles of silver salt were used. Cool the emulsion to 40°C, US Patent No. 2614929
The cells were washed by the coagulation method described in the above issue and stored at pAg = 8.0 as measured at 40°C. The resulting tabular grain AgBr emulsion has an average tabular grain diameter of 5.0 μm, an average thickness of 0.09 μm, an average aspect ratio of 56:1, and, based on the total projected area, 85% of the grains. was plate-like. Emulsion 2B Epitaxial Growth of AgCl on the Major Crystal Faces of Host Grains The AgBr host grain emulsion prepared as described above was centrifuged and 1.85 x 10 ^-2 mol of NaCl
Resuspend in solution. 40g of 2.5mol% AgCl
pAg at 40°C is 7.5 in an emulsion (0.04 mol) of
while holding at 0.55 mol NaCl and 0.50 mol
Precipitation was performed by double jet addition of AgNO ₃ solution over 4.1 minutes. This emulsion
1.0 mmol of dye A per mole of Ag, anhydro-5-chloro-9-ethyl-5'-phenyl, 3,
Spectral sensitization was performed with 3'-bis(3-sulfopropyl)oxacarbocyanine hydroxide, triethylamine salt. Selective Epitaxial Growth of Emulsion 2C AgCl at the Edge This emulsion was prepared following the same procedure as described in paragraph B above. However, in the case of this emulsion, prior to the addition of NaCl and AgNO ₃ solutions,
Spectral sensitization was performed with 1.0 mmol of dye A (per mole of Ag). In the case of emulsion 2B, which was spectrally sensitized after addition of AgCl, AgCl was randomly deposited on the crystal surface (see Figure 6). In the case of emulsion 2C, which was spectrally sensitized prior to the addition of AgCl, most
AgCl was deposited exclusively along the edges of the particles (see Figure 7). Generally, the few small grains present (shown as resting on the major crystal faces of the tabular grains) are not attached to the tabular grains by epitaxial growth, but are independent grains. Emulsions 2B and 2C were deposited with silver on a polyester support.
A coverage of 1.61 g/m ² and gelatin 3.58 g/m ² was applied. A gelatin layer of 0.54 g/m ² was coated on top of this emulsion layer. The emulsion coating film is coated in steps with a density of 0 to 6.0.
600W through tablet (0.30 steps)
2850 = exposed to a tungsten light source for 1/10 second and processed in a time development system for 1 to 20 minutes in N-methyl-p-aminophenol sulfate (Metol)-hydroquinone developer at 20°C. . The sensitometric measurement results obtained are listed in the table below.

[Table] Example 3 This example describes the epitaxial growth of AgCl at the corners of a tabular host crystal that is not spectrally sensitized. Control Emulsion 3A Random Epitaxial Growth of AgCl on the Major Crystal Faces of the Host Grains The tabular host grain AgBr emulsion 2A described in Example 2, paragraph A above, was centrifuged and 1.85×
Resuspended in 10 ⁻² molar NaCl solution. 2.5 mol% AgCl in 40 g of host emulsion (0.04 mol)
0.55 mol while keeping the pAg at 7.5 at 40 °C.
Precipitation was achieved by double jet addition of NaCl and 0.5M AgNO ₃ solution over 4.1 minutes. This emulsion was then spectrally sensitized with 1.0 mmol of dye A per mole of Ag. Emulsion 3B Selective epitaxial growth of AgCl on the corners of host grains 0.5 to 400 g of AgBr host grain Emulsion 2A (0.4 mol)
5.0 mol% iodide, 4.0 x 10 ^-2 mol KI solution
Addition was made through infusion over 10 minutes at ml/min. This emulsion is centrifuged and
Resuspended in 1.85×10 ⁻² molar NaCL solution.
2.5 mol % AgCl was then added to 40 g of the host emulsion (0.04 mol) with 0.55 mol NaCl and 0.50 mol while keeping the pAg at 40°C at 7.5 g.
Precipitation was carried out by double jet addition of AgNO ₃ solution over 4 minutes. The emulsion was then spectrally sensitized with 1.0 mmole of Dye A (per mole of Ag). Control Emulsion 3C Iodide-doped control grains containing no AgCl Emulsion 3C was prepared and spectrally sensitized following the same procedure as Emulsion 3B above. However, in this emulsion
Epitaxial growth of AgCl was omitted. In the case of emulsion 3A, which was spectrally sensitized after addition of AgCl, AgCl was randomly deposited over the entire main crystal plane (see Figure 8). For emulsion 3B with 0.5 mol% KI added prior to the addition of AgCl,
Most of the AgCl was deposited exclusively on the corners of the particles (see Figure 9). The small grains resting on the main crystal planes were independent and were not allowed to grow epitaxially on the main crystal planes. Emulsions 3A, 3B and
3C was coated, exposed and processed with a time development system. The obtained sensitometric measurement results are listed in the table below.

EXAMPLE 4 This example illustrates that the majority of AgCl is deposited by epitaxial growth exclusively at the corners of a spectrally sensitized tabular grain AgBr emulsion. Emulsion 4A Tabular AgBr host grains at 80°C containing 0.067 moles of sodium bromide
A 0.1 molar NaBr solution and a 0.1 molar AgNO ₃ solution were added to a 15% gelatin solution 3.0 ml while stirring and by double-jet method over 3.75 min, maintaining a pBr of 1.17 (silver nitrate). (consuming 0.22% of total usage). Then,
A 3.0 molar NaBr solution and a 3.0 molar AgNO ₃ solution were added simultaneously at an accelerated flow rate (24.8× from start to finish) over 31 min while maintaining pBr = 1.17 (of the total amount of silver nitrate used). consumed 91.0%). Stop adding NaBr solution, and at 7.75
Until pAg is achieved (of total silver nitrate usage)
(consumed 6.8%) continued addition of _AgNO3 solution. In total, approximately 6.85 moles of silver nitrate were used. 40 emulsion
℃, washed by the coagulation method described in U.S. Pat. No. 2,614,929, and measured at 40℃ to pAg=
Saved in 8.5. The tabular grain AgBr emulsion obtained had an average grain diameter of 2.9 μm, an average thickness of 0.11 μm, and an average aspect ratio of 26:1.
Based on the total projected area, 96% of the particles were tabular. Emulsion 4B Epitaxial growth of AgCl on the corners of host grains 0.1 mol of AgNO ₃ solution was added to 40 g of tabular grain AgBr host emulsion 4A (0.04 mol) prepared as above to adjust pAg to 7.2 at 40°C. did.
This emulsion was mixed with 1.6 mmol/Ag 1 mol of dye B,
Spectrally sensitized with 1,1'-diethyl-2,2'-cyanine p-toluenesulfonate and stirred at 40°C for 5 minutes. Then 1.0ml 0.5mol
NaCl solution was added. Then, 5.0 mol%
AgCl in host grain emulsion, pAg at 4.0℃
Precipitation was carried out by double jet addition of a 0.52 molar NaCl and 0.5 molar AgNO ₃ solution over a period of 8 minutes, while holding the pH at 7.2. FIG. 10 is a carbon replica electron micrograph of grains of an AgCl/AgBr epitaxially grown emulsion. Example 5 In this example, on a tabular grain AgBrI emulsion,
Selective epitaxial corner growth of AgCl will be explained. Emulsion 5A Tabular AgBrI (6 mol% iodide) host grains 1.5 at 55°C containing 0.12 mol potassium bromide
A 1.12 molar KBr solution containing 0.06 molar KI and a 1.0 molar AgNO ₃ solution were added to a 6.0% gelatin solution while stirring it and by double-jet method over a period of 8 minutes (5.0 molar of the total amount of silver nitrate used). %). At the same time, the temperature was increased to 70°C for 7 minutes. Then 0.12 mol of KI is included
A 2.0 molar KBr solution and a 2.0 molar AgNO ₃ solution were added simultaneously over 30 min at an accelerated flow rate (4.0x from start to finish) while maintaining pBr = 0.92 at 70 °C (total amount of silver nitrate used). (consumed 95.0% of the total). In total, about 3.16 moles of silver salt were used. The emulsion was cooled to 35°C, washed by the coagulation method described in U.S. Pat. No. 2,614,929, and measured at 35°C.
Stored at pAg=8.2. Obtained tabular grains
The AgBrI (6 mol% iodide) emulsion has tabular grains with an average grain diameter of 2.7 μm, an average thickness of 0.08 μm,
The average aspect ratio was 34:1, and 85% of the grains were tabular, based on the total projected area. Emulsion 5B Selective epitaxial growth of AgCl on the corners of host grains To 40 g of tabular grain AgBrI host emulsion 5A (0.04 mol) prepared as above was added 0.1 mol of AgNO ₃ solution to give a pAg of 7.2 at 40°C. Adjusted.
1.0 ml of 0.54 molar NaCl solution was added. This emulsion was spectrally sensitized with Dye A at 1.0 mmol/1 mole of Ag. 5.0 mol % AgCl was then added into the host tabular grain emulsion by double jet addition of 0.54 mol NaCl and 0.50 mol AgNO ₃ solution over 7.8 minutes while maintaining the pAg at 40°C at 7.5. , precipitated. Figures 11a and 11b are emulsions, respectively.
This is a secondary electron micrograph of 5B. These photographs show 5.0 mole % AgCl deposited epitaxially at the corners of a tabular grain AgBrI (6 mole % iodide) crystal. Example 6 This example describes selective epitaxial growth corner deposition of AgBr on a spectrally sensitized tabular grain AgBrI emulsion. Emulsion 6A Tabular AgBrI (12 mol% iodide) host grains 1.5 at 55°C containing 0.14 mol potassium bromide
Stir it to 9.0% gelatin solution.
A 2.0M _AgNO3 solution was added over 15 seconds (consuming 0.4% of the total silver nitrate usage). Next, 0.24 mol of KI was added using the double-jet addition method.
2.05 mol KBr solution containing and 2.0 mol
_AgNO3 solution was added over 15 seconds (consuming 0.4% of total silver nitrate usage). Next, the above halide and silver nitrate solutions were simultaneously mixed with pBr.
= 0.92 over a period of 7.5 minutes (consuming 2.3% of the total amount of silver nitrate used). The halide and silver nitrate solutions described above were then added simultaneously over 41 minutes at an accelerated flow rate (6.6x from start to finish) while maintaining pBr = 0.92 (96.9% of the total amount of silver nitrate used). ). Cool the emulsion to 35°C, US Patent No. 2614929
The cells were washed by the coagulation method described in the above issue and stored at pAg = 8.2 measured at 40°C. The resulting tabular grain AgBrI (12 mol% iodide) emulsion had an average grain diameter of 2.1 μm and an average thickness of
0.10μm, average aspect ratio 21:1, and
Based on the total projected area, 75% of the particles were tabular. Emulsion 6B Selective epitaxial growth of AgBr on the corners of host grains Tabular grains AgBrI prepared as above
(Iodide 12 mol%) Host grain emulsion 6A (0.06 mol)
A 0.2M AgNO ₃ solution was added to 56.8g to adjust the pAg at 40°C to 7.6. This emulsion was spectrally sensitized with 1.5 mmol/mol of Ag of Dye A and
It was held for 5 minutes. 4.2 mol% AaBr was then added to the host tabular grain emulsion with Na ₂ S ₂ O ₃ .5H ₂ O while maintaining the pAg at 40°C at 7.2.
(20.8 mg/) and KAuCl ₄ (20.8 mg/) by double-jet addition of a 0.2 molar NaBr solution and a 0.2 molar AgNO ₃ solution over 12.8 minutes. The emulsion was heated to 60°C and held for 10 minutes. Study on inhibited development Chemically sensitized tabular grains prepared as above
AgBr/AaBrI emulsion 6B was coated on a cellulose ester support at a coverage of 1.07 g/m ² silver and 2.15 g/m ² gelatin. The coating was given a D _nax exposure from a 600 W 3000 tungsten light source for 1/100 second and then processed in Developer A described below at 20°C for 75 seconds. Developer A Hydroquinone 10.0g Na ₂ SO ₃ 10.0g Sodium metaborate 10.0g Add distilled water Total volume 1.0 PH = 9.4 After development, the coating film was immersed in a 1% acetic acid stop bath for 1 minute, and then Washed with distilled water. FIG. 12 is a gelatin capsule electron micrograph of partially developed particles. In this photo, the blackest part represents the developed silver. The location of the developed silver indicates that most of the latent image formation occurs exclusively at or near the corners of the tabular grains. Example 7 This example illustrates sensitivity and minimum concentration as a function of epitaxy both new and after storage. This example also describes the positioning of latent image formation by inspection of partially developed particles. Emulsion 7A Chemically and spectrally sensitized AgBrI (6 mol% iodide)
Host Grain Emulsion 1A Tabular AgBrI (6 mol % iodide) Host Grain Emulsion 1A with mg/Ag mol Na ₂ S ₂ O ₃ 5H ₂ O and 5
Chemically sensitized with KAuCl ₄ at 60 °C for 10 min at 1 mg/mol of Ag, and then 1.5 mmol/mol/Ag.
Spectral sensitization was performed using Dye A with 1 mole of Ag. This emulsion was coated on a polyester support at a coverage of 1.61 g/m ² silver and 3.58 g/m ² gelatin. This emulsion layer was overcoated with a 0.54 g/m ² gelatin layer. Emulsion 7B Spectrally sensitized epitaxially grown AgCl/AgBrI
Emulsion The pAg at 40° C. was adjusted to 7.2 by simultaneous addition of 0.1 mole AgNO ₃ and 0.006 mole KI to tabular AgBrI (6 mole % iodide) host grain Emulsion 1A (0.04 mole). Then 0.80 for 1.0ml
A molar NaCl solution was added. This emulsion was spectrally sensitized with Dye A at 1.5 mmol/mol of Ag. Then,
1.25 mol% AgCl in the host tabular grain emulsion;
0.54 mol while keeping the pAg at 7.5 at 40°C.
Precipitation was carried out by double jet addition of NaCl and 0.50 molar AgNO ₃ solution over 2 minutes. Emulsion 7C Chemically and spectrally sensitized epitaxial growth
AgCl/AgBrI Emulsion The pAg at 40°C was reduced by simultaneously adding 0.1 mol AgNO ₃ and 0.006 mol KI to tabular AgBrI (6 mol % iodide) host grain emulsion 1A.
Adjusted to 7.2. Then 1.0 ml of 0.74 molar NaCl solution was added. The emulsion was spectrally sensitized with 1.5 mmol/mol Ag of Dye A and held at 40°C for 30 minutes. The emulsion was centrifuged and resuspended twice in 1.85 x 10 ^-2 molar NaCl solution. Then 1.25 mol% AgCl
In 40 g of tabular grain host emulsion (0.04 mol),
0.54 mol while keeping the pAg at 7.5 at 40 °C.
Precipitation was carried out by double jet addition of NaCl and 0.50M AgNO ₃ solution over 2.1 minutes. This emulsion was further added to 0.5mg/1 mole of Ag.
Na ₂ S ₂ O ₃ 5H ₂ O and 0.5 mg/Ag mol KAuCl ₄
Chemically sensitized with The chemical sensitizer was added 15 seconds after starting the addition of NaCl and AgNO ₃ reagents. Figure 13 is an electron micrograph of this emulsion showing selective epitaxy at the corners. Emulsion 7D Chemically and spectrally sensitized epitaxial growth
AgCl/AgBrI Emulsion Emulsion 7D was prepared in the same manner as Emulsion 7C.
However, in the case of this emulsion, in the process of epitaxial growth of AgCl on the spectrally sensitized AgBrI host crystal, the emulsion was mixed with 1.0 mg/1 mole of Ag and 1.0 mg/mol of _KAuCl4 .
Chemical sensitization was performed with 1 mol of Ag of Na ₂ S ₂ O ₃ .5H ₂ O. The emulsion described above was coated, exposed and processed in a time development system as described in Example 2 above. The sensitometric measurement results are listed in the table below.

[Table] As is clear from the table above, the spectrally sensitized epitaxially grown AgCl/AgBrI tabular grain emulsions 7B, 7C and 7D, with or without chemical sensitization, Significantly higher sensitivity than spectrally sensitized host grain AgBr emulsion 7A (
1.2log E). Furthermore, significantly less chemical sensitizer was used in emulsions 7C and 7D than in emulsion 7A. Furthermore, coatings of emulsions 7A and 7C were held at 49°C and 50% relative humidity (RH) for one week,
and a step tablet with a density of 0 to 6.0 (0.30
The sample was exposed to a 600 W 2850 tungsten light source for 1/10 second through a 600 W 2850 tungsten light source and treated with a 20 DEG C. N-methyl-p-aminophenol sulfate (Metol)-hydroquinone developer for 6 minutes. Sensitometric measurements showed that epitaxially grown AgCl/AgBrI emulsion 7C was more sensitive and produced less fog than host grain AgBrI emulsion 7A. Please refer to table.

Table: Inhibited development studies Tabular grain AgBrI (6 mol % iodide) emulsion 7A and epitaxially grown AgCl/AgBrl emulsion 7C were deposited on a cellulose ester support with 1.61 g/m ² of silver and 3.58 g/m ² of gelatin. It was applied in a covering amount. The resulting emulsion layer was overcoated with a 0.54 g/m ² gelatin layer. The coating of Emulsion 7A was given a D _nax exposure from a 600 W 2850 tungsten light source for 1/10 second and then processed in Developer B below for 50 seconds at 20°C. Also 600W2850 for the coating film of emulsion 7C
D _nax exposure was applied from a tungsten light source through a 2.0 neutral density filter for 1/10 second and processed in developer B at 20°C for 60 seconds. Developer B Hydroquinone 0.4g Elon (N-methyl-p-aminophenol sulfate) 0.2g Na ₂ SO ₃ 2.0g KBr 0.5g Sodium metaborate 5.0g Add distilled water Total amount 1.0 PH = 10.0 After development, paint film was immersed in a 0.5% acetic acid stop bath for 30 seconds and then washed with distilled water for 2 minutes. FIG. 3 is a gelatin capsule electron micrograph of partially developed emulsion 7A grains. The location of the developed silver (blackest area) indicates that latent image formation occurred primarily randomly along the edges of the tabular grains. Shown in FIG. 2 are grains of partially developed emulsion 7C. It can be seen from FIG. 2 that most of the latent image formation occurred exclusively near the corners of the tabular grains. Example 8 In this example, tabular grain epitaxial growth
The photographic response of AgCl/AaBrI emulsion,
Spectral sensitization before attachment of AgCl vs. spectral sensitization after attachment of AgCl will be explained. Emulsion 8A Selective epitaxial growth of AgCl on the corners of host grains (spectral sensitization was performed prior to silver chloride precipitation) Tabular AgBrI (6 moles iodide) host grain emulsion
The pAg at 40 was adjusted to 7.2 by simultaneously adding 0.10M AgNO ₃ and 0.006M KI solution to 1A.
1.0 ml of 0.74 molar NaCl solution was added. This emulsion was spectrally sensitized with 1.5 mmol/1 mol of Ag dye A,
It was then held at 40°C for 30 minutes. The emulsion was then centrifuged and resuspended twice in 1.85 x 10 ^-2 molar NaCl solution.
Then, 1.25 mol% AgCl was added to the tabular host emulsion at a concentration of 0.54 while keeping the pAg at 40°C at 7.5.
By double-jet addition of 0.50 molar NaCl and 0.50 molar AgNO ₃ solutions over 2 minutes,
precipitated. 15 seconds after starting the addition of the NaCl and AgNO ₃ reagents, 0.5 mg of Na ₂ S ₂ O ₃ .5H ₂ O/1 mole of Ag and 0.5 mg of KAuCl ₄ /1 mole of Ag were added. Emulsion 8B Random epitaxial growth of AgCl on major faces of host grains (spectral sensitization was performed after silver chloride precipitation) Emulsion 8B was prepared according to the same procedure as Emulsion 8A above. However, for this emulsion, the AgCl deposition was followed by spectral sensitization with Dye A at 1.5 mmol/Ag1 mole. The electron micrograph of emulsion 8A, which was spectrally sensitized prior to the addition of AgCl, shows that AgCl is exclusively tabular.
It was found that it was deposited near the corners of the AgBrI crystal. However, for emulsion 8B (AgCl deposition followed by spectral sensitization),
It was found that AgCl was deposited randomly on the main crystal faces. Emulsions 8A and 8B were coated on a cellulose triacetate support at a coverage of 1.60 g/m ² silver and 3.58 g/m ² gelatin and exposed and processed in a time development system similar to that described in Example 2 above. did. From the results of sensitometry measurements, it was found that at equal D _nio (0.10), emulsion 8A had a higher sensitivity by 0.70 logE than emulsion 8B. Example 9 This example describes the photographic response of a tabular AgCl/AgBrI emulsion with spectral sensitization performed before addition of AgCl. Emulsion 9A Selective epitaxial growth of AgCl on the corners of host grains 40 g tabular AgBrI (6 moles iodide) host grain Emulsion 1A with 0.10 moles AgNO ₃ and 0.006 moles KI
was added at the same time to adjust the pAg at 40°C to 7.2. Then 1.0 ml of 0.8 molar NaCl solution was added.
This emulsion was mixed with 1.8 mmol/Ag1 mole of dye C, anhydro-9-ethyl-5,5'diphenyl-3,
Spectrally sensitized with 3'-bis(3-sulfobutyl)oxacarbocyanine hydroxide, triethylamino salt and held at 40°C for 30 minutes.
1.25 mol% AgCl was then added into the tabular grain host emulsion by double-jet addition of 0.54 mol NaCl and 0.50 mol AgNO ₃ solution over 2 minutes while maintaining the pAg at 40°C at 7.5. , precipitated. Emulsion 9B Au-sensitized selective epitaxial growth of AgCl on the corners of host grains Emulsion 9B was prepared following the same procedure as Emulsion 9A above. However, in the case of this emulsion, NaCl and
15 seconds after start of addition of _AgNO3 reagent, 1.0 mg
1 mole of KAuCl ₄ /Ag was added. Emulsion 9C Sulfur-sensitized selective epitaxial growth of AgCl on the corners of host grains Emulsion 9C was prepared following the same procedure as Emulsion 9A above. However, in the case of this emulsion, NaCl and
15 seconds after start of addition of _AgNO3 reagent, 1.0 mg
₁ mole _{of Na2S2O3.5H2O /} Ag was added. Furthermore, after the formation of the precipitate was completed, the emulsion was heated at 60°C for 10
Heated for minutes. Emulsion 9D Selenium (Se) Sensitized Selective Epitaxial Growth of AgCl on the Corners of Host Grains Emulsion 9D was prepared following the same procedure as Emulsion 9A above. However, in the case of this emulsion, NaCl and
15 seconds after the start of the addition of the AgNO ₃ reagent, 0.17 mg of sodium selenite (Na ₂ SeO ₃ )/1 mole of Ag was added. Emulsions 9A and 9B were coated on a cellulose triacetate film support at a coverage of 1.15 g/m ² silver and 3.5 g/m ² gelatin. Additionally, tabular AgBrI host grain emulsion 1A was spectrally sensitized with 1.87 mg/Ag mole of Dye C and coated as described above. moreover,
First, 5 mg of tabular grain AgBrI host emulsion was added.
KAuCl ₄ /Ag1 mol + 5mgNa ₂ S ₂ O ₃・5H ₂ O /Ag1
chemically sensitized for 10 minutes at 60° C. and then spectrally sensitized with Dye C at 1.87 mg/Ag mole;
It was then applied as described above. These coatings were exposed to a 600W 5500〓 tungsten light source for 1/10 of a second through a continuous wedge doublet with a density of 0 to 4.0 and then exposed to a 600W 5500〓 tungsten light source for 1/10 second in a N-methyl-p-aminophenol sulfate (Metol)-hydroquinone developer. The mixture was treated at 20°C for 6 minutes. From the sensitometric measurement results, epitaxially grown AgCl/AgBrI emulsions 9A to 9D are spectrally sensitized.
Significantly higher sensitivity (>
2.0logE) and higher D _nax . Please refer to the table below. Example 10 This example describes the epitaxial growth of AgBr at the corners of a spectrally sensitized tabular AgBrI crystal. Emulsion 10A Selective epitaxial growth of AgBr on the corners of tabular AgBrI (6 mol% iodide) host grains Tabular AgBrI (6 mol% iodide) host emulsion 1A
was spectrally sensitized with 1.5 mmol/mol of Ag of dye A. Spectral sensitization Subsequently, the emulsion was centrifuged and suspended twice in distilled water. Then, 0.6 mol% AgBr was added into 40 g of spectrally sensitized AgBrI host grain emulsion (0.04 mol) at 40°C.
0.2M NaBr and 0.2 while keeping pAg at 7.5
Precipitation was carried out by double-jet addition of molar AgNO ₃ solution over 1.5 minutes. NaBr
and 1.0 mg 15 seconds after the start of addition of _AgNO3 reagent.
_Na2S2O3・_{5H2O / As1mol} and 1.0mg
1 mole of KAuCl ₄ /Ag was added. See Figure 14 for a carbon replica electron micrograph of the epitaxially grown AgBr/AgBrI emulsion. 4.0 mg of tabular AgBrI host grain emulsion 1A
KAuCl ₄ /Ag 1 mol and 5.0 mg Na ₂ S ₂ O ₃ .
Chemical sensitization was carried out with 5H ₂ O/1 mole Ag for 10 minutes at 60° C. and then spectrally sensitized with 1.5 mmol/1 mole Ag of dye A. Host grain emulsion 1A and epitaxially grown AgBr/AgBrI emulsion were prepared in Example 2 above.
It was coated, exposed and processed as described in . The sensitometric measurements show that epitaxially grown emulsion 10A, sensitized at low temperatures with significantly lower amounts of chemical sensitizers, exhibits higher sensitization than sensitized AgBrI host grain emulsion 1A at equal D _nio (0.10). about
It can be seen that the sensitivity is high by 0.80logE.

[Table] Particles

1A AgBr host (1.87) KAuCl ₄ (
5)＋64 0.68 0.10 0.77
Particle NA ₂ S ₂ O ₃・
5H ₂ O(5)

Table Example 11 This example describes the epitaxial growth of AgCl on a tabular AgBr grain emulsion sensitized with a supersensitizing dye conjugate. Emulsion 11A This emulsion was prepared in the same manner as tabular AgBr host grain emulsion 2A of Example 2 above. The average grain diameter of the obtained emulsion was 3.9 μm, and the average grain thickness was
It was 0.09 μm. Particles with a thickness of less than 0.3 micrometer and a diameter of at least 0.6 micrometer exhibited an average aspect ratio of 43:1 and occupied 90% of the total projected area of the silver bromide grains. Emulsion 11B Selective epitaxial growth of AgCl/AgBr on host grain corners of emulsion spectrally sensitized with dye conjugates 40 g of tabular AgBr host grain emulsion 11A (0.04 mol) was added with 0.1 mol of AgNO ₃ solution to 40 The pAg at °C was adjusted to 7.2. Then 1.0 ml of 0.61 molar NaCl solution was added. This emulsion was spectrally sensitized with Dye B at 1.5 mmol/mol of Ag. 1.25 mol % AgCl was precipitated into the host tabular grain emulsion by double jet addition of 0.54 mol NaCl and 0.50 mol AgNO ₃ solution over 2 minutes while maintaining the pAg at 7.5 at 40°C. I let it happen. Sensitometric measurement results Coating film 1: Tabular AgBr host grain emulsion 11A was spectrally enhanced with 1.5 mmol/Ag1 mole of dye B and 0.15 mmol/Ag1 mole of dye D, 2-(p-diphenylaminostyryl)benzothiazole. The polyester was then coated onto the support at a coverage of 1.73 g/m ² silver and 3.58 g/m ² gelatin. This emulsion layer was overcoated with 0.54 g/m ² of gelatin. Coating film 2: 1.5 mg of tabular AgBr host grain emulsion 11A
KAuCl ₄ /Ag1 mol + 1.5mgNa ₂ S ₂ O ₃・5H ₂ O /
Chemical sensitization was performed with 1 mole of Ag at 65°C for 10 minutes. This emulsion was then spectrally sensitized and coated as described for Coating 1 above. Coating 3: Tabular grain epitaxially grown AgCl/AgBr emulsion 11B spectrally sensitized with Dye B, followed by silver chloride deposition, further sensitized with Dye D at 0.15 mmol/Ag mole, and then The coating was applied as described for Coating 1 above. The resulting coating was exposed as described in Example 2 above and processed in a time development system. The obtained sensitometric measurement results are shown in the table below.

[Table] Particles
3 AgCl／AgBr Dya B(1.5)＋ D(0.15)
…386 0.20
As can be seen from the above, epitaxially grown AgCl/AgBr emulsion 11B, spectrally sensitized prior to AgBr deposition, was 131 log sensitivity units more sensitive than spectrally sensitized host grain emulsion 11A. In addition, this emulsion 11B has a 63 log
Only the sensitivity unit was highly sensitive. Example 12 In this example, a tabular grain AgBrI emulsion contains fine grains.
An epitaxially grown AgCl/AgBrI emulsion prepared by adding an AgCl emulsion will be described. Emulsion 12A Fine grain AgCl emulsion A 3.3% gelatin solution containing 3.4 x 10 ^-3 moles of NaCl was added to a 3.0% gelatin solution with stirring and by the double jet method for 0.4 minutes at pAg = 6.9.
A molar sodium chloride solution and a 4.0 molar silver nitrate solution were added. A 0.24 molar AgCl emulsion was obtained. Emulsion 12B Epitaxial growth containing 2.5 mol% AgCl
AgCl/AgBrI Emulsion 30 g of tabular grain AgBrI (6 mole % iodide) Emulsion 1A was spectrally sensitized with 1.1 mmol/Ag mole Dye 1 and held at 40°C for 15 minutes.
Next, 10 g of AgCl emulsion 12A (1 x 10 ^-3 mol) prepared as described above was added to the tabular grain AgBrI emulsion.
1A (0.04 mol) and stirred at 40°C for 30 minutes. Electron micrographs show that AgCl was deposited at the corners of the tabular AgBrI crystals as a result of selective epitaxial growth. Please refer to FIG. 15, which shows an electron micrograph. Example 13 In this example, when a sufficient amount of iodide is present in the tabular silver bromoiodide host grains, even in the absence of an adsorbed locally dominant substance, those host grains The fact that AgCl can be epitaxially grown selectively on corners will be explained. Emulsion 13A This emulsion was prepared by double-jet precipitation with tabular AgBrI (12 mole % iodide) host grains.
It had an average particle diameter of 3.6 μm, and an average particle thickness of 0.09 μm. Particles with a thickness of less than 0.3 mitarometers and a diameter of at least 0.6 micrometers had an average aspect ratio of 40:1 and occupied more than 85% of the total projected area of all particles present. The particles contained 12 mole percent iodide, which had been uniformly introduced during the double jet precipitation process. This emulsion is 0.6 mmol/
Spectral sensitization was performed with Dye A containing 1 mole of Ag. Emulsion 13B Emulsion 13B was prepared according to the same procedure as Emulsion 13A. However, in the case of this emulsion, chemical sensitization of the emulsion was performed prior to spectral sensitization. This chemical sensitization consisted of 3.4 mg of Na ₂ S ₂ O ₃ 5H ₂ O/mol of Ag and 1.7 mg of
of KAuCl/Ag for 10 minutes at 65°C. Emulsion 13C Spectral sensitization after selective epitaxial corner growth Tabular grain AgBrI (12 mol% iodide) Emulsion 13A
pAg at 40 °C to 7.2 by simultaneous addition of 0.1 M AgNO ₃ and 0.012 M KI solution to
It was adjusted to This emulsion was centrifuged and 1.85
Resuspended in ×10 ⁻² molar NaCl solution. 2.5 mol% AgCl was added to 40 g of a tabular host grain emulsion (0.04
mol) by double-jet addition of 0.55 molar NaCl and 0.5 molar AgNO ₃ solution over 4 minutes while maintaining the pAg at 7.5 at 40°C. This emulsion was then spectrally sensitized with 0.6 mmol of dye A per mole of Ag. For emulsion 13C spectrally sensitized after addition of AgCl,
Most of the AgCl was deposited exclusively at the corners of the tabular AgBrI crystals. 16th
The figure is a carbon replica electron micrograph of Emulsion 13C. Emulsions 13A, 13B and 13C were coated, exposed and processed in a time development system as described in Example 2 above. The sensitometric measurement results are listed in the table below.

[Table] Child emulsion

EXAMPLE 14 This example illustrates that epitaxial growth of AgCl on a spectrally sensitized tabular grain AgBrI emulsion can be confined to less than the entire corner region. Emulsion 14A Selective epitaxial growth of AgCl on the corners of host grains Emulsion 14A was prepared similarly to AgBr host grain emulsion 1A described in Example 1 above. After precipitation, the pAg at 40°C was reduced to 7.2 by simultaneously adding 2.0 mol of AgNO ₃ and 0.12 mol of KI to this emulsion.
It was adjusted to Next, sodium chloride was added to adjust the concentration of chloride ions in the emulsion to 1.8×10 ⁻² mol/. This emulsion was mixed with 1.5 mmol/Ag1 mol of dye A.
and held at 40°C for 30 minutes. Then 1.2 mol % AgCl was added into the host emulsion (3.9 mol) of 9.5 mol 2.19 mol NaCl and 2.0 mol NaCl while maintaining the pAg at 40°C at 7.2.
Precipitation was achieved by double jet addition of AgNO ₃ solution over 4 minutes. Electron micrographs of emulsion 14A show that AgCl growth on the spectrally sensitized tabular grain AgBrI (6 mol % iodide) emulsion was generally confined to six or fewer corner sites for each hexagonal tabular crystal. It turned out that. FIG. 17 shows a representative electron micrograph of this. Example 15 In this example, the central annular region of a tabular silver bromoiodide host grain with low iodide content is
Selective epitaxial growth of AgCl will be explained. Emulsion 15A Tabular AgBrI (12 mol % iodide) host grains with a central zone of AgBr were added to a 1.5% gelatin solution containing 0.12 mol of potassium bromide at 55°C with stirring and by the double jet method. A 1.12 molar KBr solution containing 0.12 molar KI and a 1.0 molar AgNO ₃ solution at pBr = 0.92 were added in 1 minute (consuming 0.6% of the total silver nitrate usage). The temperature was then raised to 70°C within 7 minutes. Then a constant
2.0 containing 0.24 mol KI while maintaining pBr
molar KBr solution and 2.0 molar _AgNO3 solution simultaneously at accelerated flow rate (2.75× from start to finish)
and was added over a period of 17.6 minutes (consuming 29.2% of the amount of silver nitrate used). The temperature was lowered to 55°C. 0.92
2.0 M KBr solution and 2.0 M while keeping pBr of
Molar AgNO ₃ solution was added over 2.5 minutes (consuming 11.7% of the total silver nitrate usage). Then,
2.0 molar KBr solution containing 0.24 molar KI and
2.0M _AgNO3 solution simultaneously at 55℃
It was added over a period of 12.5 minutes (consuming 58.5% of the total amount of silver nitrate used) while maintaining a pBr of 0.92.
In total, about 3.4 moles of silver salt were used. The emulsion was cooled to 35°C, washed by the coagulation method described in U.S. Pat. No. 2,614,929, and measured at 40°C.
Stored at pAg=8.4. Obtained tabular grains
AgBrI (12 mol% iodide) has an average tabular grain diameter of 1.8 μm and an average grain thickness of
It was 0.13 μm. Particles having a thickness of less than 0.3 micrometers and a diameter of at least 0.6 micrometers have an average aspect ratio of 13.8:1;
And it occupied 80% of the total projected area of the particles. Emulsion 15B Selective epitaxial growth of AgCl on the annular sites of host grains 40 g of tabular AgBrI prepared as above
(12 mol % iodide) Host grain emulsion 15A (0.04 mol) was adjusted to have a pAg of 7.2 at 40°C by adding 0.1 mol AgNO ₃ solution. Then 1.0ml
A 0.74 molar NaCl solution was added. 5 mol % AgCl was then precipitated to the tabular host grain emulsion by double jet addition of 1.04 M NaCl and 1.0 M AgNO ₃ solution over 1 minute while maintaining the pAg at 7.5 at 40°C. I let it happen. Emulsion 15C Selective epitaxial growth of AgCl on a few sites contained in the annular region of the host grain Emulsion 15C was prepared in the same manner as Emulsion 15B.
However, in the case of this emulsion, the pAg at 40°C is 7.5.
0.55M NaCl and 0.5M AgNO ₃ reagent were added to the buffer held at 7.8 minutes. A carbon replica electron micrograph of epitaxially grown AgCl/AgBrI emulsion 15B is shown in FIG. In the precipitation process of tabular AgBrI crystals
Concentric internal hexagonal (triangular) rings of AgBr were formed and AgCl was selectively deposited onto such AgBrI crystals. Here, the adhesion of AgCl by epitaxial growth forms a discontinuous crystal.
It may be noted that the 12 mole % iodide tabular crystals were not spectrally sensitized. Similar results were observed for emulsion 15C. However, in the case of this emulsion, the slower the deposition rate of silver chloride by epitaxial growth, the fewer the number of epitaxially grown grains, and therefore the greater the degree of individual growth. Example 16 This example describes the epitaxial growth of AgCl in the peripheral AgBr region of a tabular AgBrI grain. Emulsion 16A Tabular AgBrI (12 mol % iodide) host grains with peripheral AgBr areas (16.6 mol % of total) were stirred into a 1.5% Seratin solution containing 0.12 mol potassium bromide 6.0 at 55°C. However, in a double jet method, a 1.12 molar KBr solution containing 0.12 molar KI and a 1.0 molar AgNO ₃ solution were added at pBr=0.92 within 1 minute (consuming 0.5% of the total amount of silver nitrate used). The temperature was then raised to 70°C within 7 minutes. Then a constant
2.0 containing 0.24 mol KI while maintaining pBr
molar KBr solution and 2.0 molar _AgNO3 solution simultaneously at accelerated flow rates (4.0× from start to finish)
(consuming 82.9% of the total amount of silver nitrate used) over a period of 30 minutes.The temperature was lowered to 55°C.
2.0 molar KBr solution and while maintaining a pBr of 0.92.
A 2.0M _AgNO3 solution was added over 3.75 minutes (consuming 16.6% of the total silver nitrate usage). In total, about 3.6 moles of silver salt were used. Emulsion at 35℃
pAg=
Saved in 8.4. The resulting tabular grain AgBrI (12 mole % iodide) emulsion had an average tabular grain diameter of 2.2 μm and an average thickness of 0.09 μm. Thickness less than 0.3 micrometers and minimum 0.6
The particles with a micrometer diameter had an average aspect ratio of 24:1 and occupied 80% of the total projected area of the particles. Epitaxial Growth of AgCl in the Periphery of Emulsion 16B Tabular AgBrI (12 mol % iodide) host grain Emulsion 16A was dispersed in 2.5 times its volume of distilled water, centrifuged, and then resuspended in distilled water. Made it muddy. Final silver content is 1 mol of Ag (per 1 kg of emulsion)
It was hot. 2.5 mole % AgCl was then precipitated onto 0.04 mole host emulsion 16A. To do this, while keeping the pAg at 6.75 at 40°C,
0.8 mol of 0.25 mol NaCl and 0.25 mol _AgNO3 solution
A double jet addition was made over a period of minutes. Then,
This emulsion was spectrally sensitized with Dye A at 1.0 mmol/1 mole of Ag. Electron micrographs of Emulsion 16 revealed that the AgCl was deposited by epitaxial growth along the edges of the spectrally unsensitized AgBrI (12 mole % iodide) host grain emulsion.
Selective growth of AgCl occurred in the peripheral region of the AgBrI host crystal. FIG. 19 shows a representative electron micrograph of this. Emulsion 16C Sensitization of Emulsion 16A A portion of Emulsion 16A contains 3.0 mg/1 mole of Ag.
Na ₂ S ₂ O ₃ 5H ₂ O and 1.5 mg/Ag mole KAuCl ₄ were added. The mixture was heated to 65°C for 10 minutes, cooled to 40°C and finally 1.0 mmol/mol As of Dye A was added. Emulsions 16B and 16C were coated on a cellulose triacetate support at a coverage of 1.61 g/m ² silver and 3.58 g/m ² gelatin and exposed and processed in a development system for a time similar to that described in Example 2 above. did. The sensitometric measurement results revealed that at equal D _nio (0.15), emulsion 16B has a higher sensitivity than emulsion 16C by 0.16 logE. Note that emulsion 16B was not treated with either the chemical sensitizers Na ₂ S ₂ O ₃ or KAuCl ₄ . Example 17 This example describes the selective deposition of AgCl on the AgBr core of a tabular grain AgBrI emulsion. AgCl growth was internally sensitized with iridium. For this emulsion, no spectral sensitization was performed prior to the addition of AgCl. Emulsion 17A Tabular AgBrI grains with central AgBr region This emulsion was prepared by double jet precipitation. This emulsion has a central AgBr region (overall grain
6.7 mol %) and a cyclic AgBrI (12 mol % iodide) region laterally surrounding this region. This emulsion had an average grain diameter of 1.9 μm and an average grain thickness of 0.08 μm. Particles with a thickness of less than 0.3 micrometers and a diameter of at least 0.6 micrometers exhibited an average aspect ratio of 24:1 and occupied 80% of the total projected area of the particles. Emulsion 17B This emulsion was prepared by spectrally sensitizing a portion of Emulsion 17A above with 0.6 mmol/mol Ag of Dye A. Emulsion 17C Selective epitaxial growth of AgCl on the central region of host grains A portion of the emulsion 17A was dispersed in distilled water, centrifuged, and then resuspended in a 1.85 x 10 ^-2 molar NaCl solution. I let it happen. Then 10 mol% AgCl
in 40 g of tabular host grain emulsion (0.04 mol),
0.55 mol while keeping the pAg at 7.5 at 40 °C.
Precipitation was achieved by double jet addition of NaCl and 0.5M AgNO ₃ solution over 17.6 minutes. This emulsion was then spectrally sensitized with 0.6 mmol/mol of Ag of Dye A. Emulsion 17D Emulsion 17D was prepared in the same manner as Emulsion 17C.
However, for this emulsion, the iridium sensitizer was added to the emulsion 15 seconds after starting the addition of the NaCl and AgNO ₃ reagents. Emulsions 17B, 17C and 17D were coated on a polyester support at a coverage of 1.61 g/m ² silver and 3.58 g/m ² gelatin. A gelatin layer of 0.54 g/m ² was overcoated on the emulsion layer. The concentration of the obtained coating film is 0~
A 600 W 2850 Tungsten light source was exposed for 1/10 second through a 6.0 step tablet. These coatings were developed using N-methyl-p-aminophenolsulfate (Elon)-ascorbic acid developer (A) or N-methyl-p-aminophenolsulfate (Elon)-ascorpine containing 10 g/ml of sodium sulfite. 20 in acid developer (B)
℃ for 6 minutes. Through the addition of sodium sulfite, both surface and internal development became possible. Thus, developer B was an "internal" developer (also referred to as a "total" developer) as used in the art. The percentage (%) of developed silver is
Measured by line fluorescence. A curve of percentage of silver developed versus light exposure was then constructed. The results are reported in the table below.

[Table] The highest relative sensitivity was obtained when emulsion 17D doped with iridium during the AgCl deposition process was internally developed (surface plus). Emulsion 17D had low sensitivity when it was processed in surface-only developer. Emulsions 17B and 17C without iridium
It was not possible to obtain comparable results in either case. These data support epitaxially grown AgCl with iridium as internal chemical sensitizer.
It explains that it mixes into the phase. Furthermore, coating films of emulsions 17B and 17D were coated with a density of 0 to 0.6.
exposure to a 600W2850〓 tungsten light source for 1/2 second through a step tablet and for 1 minute at 20°C in a total (surface plus internal) developer of the type described in U.S. Pat. No. 3,826,654. Processed. Another set of coatings was exposed and processed in a potassium dichromate bleach bath (1.3 x 10 ^-2 moles K ₂ Cr ₂ O ₇ ,
4.7×10 ⁻² mol of H ₂ SO ₄ ) at 20° C. for 10 minutes.

[Table] As shown in the table, emulsion 17D had a 1.05 logE higher sensitivity than control emulsion 17B. Bleaching a coating of control emulsion 17B removed most of the latent image. However, when the coating of emulsion 17D was bleached, no significant loss of latent image occurred. This indicated that the latent image had very poor bleaching properties (because the latent image was located below the surface of the epitaxially grown AgCl phase). FIG. 20 is an electron micrograph of emulsion 17C showing the epitaxial growth of AgCl on the central AgBr region of the tabular AgBrI grains. FIG. 21 is a secondary electron micrograph of emulsion 17C further showing that the AgCl epitaxy is centrally located. Example 18 This example describes the controlled localized epitaxial growth of AgSCN on tabular grains of a silver bromoiodide emulsion. Selective epitaxial growth at the edge of Emulsion 18A AgSCN 40 g of tabular AgBrI (6 mol % iodide) host grain emulsion 1A (0.04 mol) as described in Example 1 above with 0.1 mol of AgNO ₃ and 0.006 mol of KI Its pAg at 40°C was adjusted to 7.2 by simultaneous addition. Then 1.0 ml of 0.13 molar NaSCN solution was added. Then, 5 mol% AgSCN was added into the host emulsion while maintaining the pAg at 7.5 at 40°C.
0.25 mol NaSCN and 0.25 mol AgNO ₃ solution
Precipitation was carried out by double jet addition over 16 minutes. Emulsion 18B Selective Epitaxial Growth of AgCN in the Corners Emulsion 18B was prepared similarly to Emulsion 18A above. However, in the case of this emulsion, NaSCN and AgN ₃
The emulsion was spectrally sensitized with 1.1 mmol/mol of Ag of Dye A prior to double jet addition. From the electron micrographs of emulsions 18A and 18B,
It can be seen that emulsion 18A, which was not spectrally sensitized prior to the addition of soluble silver and thiocyanate salts, produced selective deposition based on epitaxial growth of silver thiocyanate at the edges of the tabular AgBrI grains. Figure 22 is a typical electron micrograph of Emulsion 18A. Emulsion 18B (which was spectrally sensitized prior to epitaxy formation) also produced silver thiocyanate deposition, and most of it was exclusively at the corners of the tabular host grains. Second
Figure 3 shows this typical electron micrograph. Example 19 This example describes further chemical sensitization of a tabular grain AgBrI emulsion with selective AgSCN epitaxy at the corners. Emulsion 19A Chemically sensitized, selectively epitaxially grown AgSCN growth in the corners Tabular AgBrI (6 mol% iodide) host grain emulsion 1A with simultaneous addition of 0.1 mol AgNO ₃ and 0.006 mol KI solution at 40°C pAg was adjusted to 7.2. The emulsion was centrifuged and resuspended in distilled water. 1.0ml in 40g emulsion (0.04mol)
A 0.13M NaSCN solution was added. The emulsion was then spectrally sensitized with 1.1 mmol/mol of Ag of Dye A. Then, 2.5 mol% AgSCN was added into the host emulsion while keeping the pAg at 40 °C at 7.5.
0.25 mol NaSCN and 0.25 mol AgNO ₃ solution
Precipitation was carried out by double jet addition over a period of 8.1 minutes. Add 1.0mg of this emulsion
Na ₂ S ₂ O ₃・5H ₂ O/1 mol of Ag and 1.0 mg of KAuCl/
Chemical sensitization was performed with 1 mol of Ag (added 1 minute after starting addition of NaSCN and AgNO ₃ reagents). Emulsion 19A prepared as above was used in Example 2.
Coated, exposed and processed with a time development system as described in . Tabular AgBrI host grain emulsion 1A
7.5 mg of Na ₂ S ₂ O ₃ 5H ₂ O/Ag mol and 2.5 mg of
Chemically sensitized with KAuCl ₄ /1 mol of Ag at 65°C for 10 min to give 1.10 mmol/1 mol of Ag dye A.
and then coated and tested as described for Emulsion A above. Sensitometric measurements show that at equal D _nio levels (0.10), the epitaxially grown AgSCN/AgBrI emulsion was 0.34 logE sensitivity units more sensitive than the tabular AgBrI host grain emulsion. Example 20 In this example, on a tabular grain AgCl emulsion,
Epitaxial growth of AgSCN will be explained. Control emulsion 20A Tabular AgCl host grains containing 0.35% by weight adenine and 0.5 _% CaCl2
0.625% by weight of synthetic polymer, poly(3- ^thiapentyl methacrylate)-co-acrylic acid-co-2-methacryloyloxyethyl-1-sulfonic acid, sodium salt ( 1:2:7), solution (PH=2.6 at 55℃) 2.0
Next, 2.0 mol of CaCl ₂ solution and 2.0 mol of AgNO ₃ were added while stirring and using the double jet method.
The solution was added over a period of 1 minute (consuming 0.08% of the total amount of silver nitrate used). The chloride and silver nitrate solutions described above were then added simultaneously at controlled pCl and at accelerated flow rates (from start to finish).
2.3X) over a period of 15 minutes (consuming 28.8% of the total amount of silver nitrate used). The chloride and silver nitrate solution described above was then added over an additional 26.4 minutes (consuming 71.1% of the total amount of silver nitrate used). During approximately the first third of precipitation formation, a 0.2M NaOH solution (30.0ml) was added gradually to maintain the pH at 55°C at 2.6. A total of about 2.6 moles of silver nitrate was used. This emulsion was cooled to room temperature and 1×
Dispersed in 10 ⁻³ molar HNO ₃ , precipitated and decanted. The solid phase was resuspended in a 3% by weight gelatin solution and the pAg at 40°C was adjusted to 7.5 by addition of NaCl solution.
The resulting tabular grain AgCl emulsion had an average grain diameter of 4.3 μm and an average thickness of 0.28 μm.
Particles with a thickness of less than 0.3 micrometers and a diameter of at least 0.6 micrometers have an average aspect ratio of 15:1 and also have a
80% occupied. Selective epitaxial growth of Emulsion 20B AgSCN at the edge 0.5 mol of NaSCN in 40 g of tabular AgCl host grain emulsion 20A (0.04 mol) prepared as described above.
5 mole % of AgSCN was precipitated into the emulsion by adding 0.5 molar AgNO ₃ solution over 7.8 minutes by double jet addition method. Electron micrographs of emulsion 20B revealed that most of the AgSCN was deposited exclusively at the edges of the tabular AgCl crystals.
Figure 24 is a typical electron micrograph of this emulsion. {110} and {111} for tabular AgCl crystals
Both edges were included. However, in the case of AgSCH, it was deposited without selection at both types of edge sites. Example 21 This example describes controlled local deposition of AgBr on a spectrally sensitized tabular grain AgBr emulsion. Additional AgBr was deposited primarily on the corners, with some growth along the edges. Emulsion 21A Controlled local growth of AgBr on AgBr host grains Tabular AgBr host grain emulsion as described in Example 4 above.
A 0.1 mol AgNO ₃ solution was added to 40 g of 4A (0.04 mol) to adjust its pAg at 40°C to 7.2. This emulsion was mixed with 2.4 mmol/Ag1 mole of dye E, anhydro-5,5',6,6'-tetrachloro-1,1'-
Spectrally sensitized with diethyl-3,3'-bis(3-sulfobutyl)benzimidazolocarbocyanine hydroxide triethylamine and held at 40°C for 5 minutes. Then 6.25 mol%
AgBr was added to this tabular host grain emulsion with 0.2 mol of NaBr while keeping the pAg at 40°C at 7.2.
and 0.2M AgNO ₃ solution over 15.7 minutes. FIG. 25 shows a carbon replica electron micrograph of this emulsion. It can be seen that some silver bromide was deposited along the edges of the tabular grains. However, it is judged that the adhesion of the additional amount of silver bromide was mainly limited to the corners of the tabular grains. In electron micrographs, the small grains overlying the major faces of tabular grains are independent of the grains below them. Example 22 This example describes controlled local deposition of AgBrI on a spectrally sensitized AgBrI emulsion. Addition of AgBrI is chemically sensitized during attachment,
Then, it was selectively attached to the corners of the host particles. Emulsion 22A Tabular AgBrI (6 mol% iodide) host grain Tabular AgBrI (6 mol% iodide) host grain Emulsion 1A was mixed with 4 mg of Na ₂ S ₂ O ₃ 5H ₂ O / 1 mol of Ag + 4 mg
of KAuCl ₄ /Ag for 10 min at 60°C and then 1.2 mmol/Ag.
Spectral sensitization was performed with Dye A containing 1 mole of Ag. Emulsion 22B Selective growth of AgBrI in the corners AgBrI (6 mol% iodide) host grain emulsion 22A
was spectrally sensitized with 1.2 mmol/Ag1 mol of dye A,
Centrifuged and resuspended in distilled water. Then 2.5 mol% containing 6 mol% iodide
AgBrI was added to 40 g (0.04 mol) of the above emulsion with 0.2 mol of a solution containing 0.188 mol KBr and 0.012 mol KI while maintaining the pAg at 7.5 at 40°C.
Precipitation was performed by double jet addition of a solution of AgNO ₃ over 9.9 minutes. 15 seconds after the start of precipitation, 1.0 mg Na ₂ S ₂ O ₃ 5H ₂ O/Ag1
mol and 1.0 mg KAuCl ₄ /Ag mol were added.
After the precipitation was complete, the resulting emulsion was heated at 60°C for 10 minutes. From the electron micrograph of emulsion 22B, AgBr is
It was found that the AgBrI host grains were deposited at the corners of the emulsion. Second
Figure 6 shows a typical electron micrograph. Emulsions 22A and 22B were coated on a cellulose triacetate support at a coverage of 1.61 g/m ² silver and 3.58 g/m ² gelatin and exposed and processed in a development system for a time similar to that described in Example 2 above. did. Sensitometric measurements revealed that at equal D _nio (0.2), emulsion 22B was more sensitive than emulsion 22A by 0.62 logE. Example 23 This example describes a silver halide emulsion with tabular grains having an average aspect ratio greater than 8:1. These tabular grains have 2.44 mole percent silver chloride deposited primarily at their corners and edges. Emulsion 23A Tabular grains with an average aspect ratio of 8.1:1
AgBrI Host A Preparation of Tabular Grain AgBr Core Emulsion In a well-stirred aqueous bone gelatin (1.5% by weight) solution containing 0.142 moles of potassium bromide,
A 1.15 molar potassium bromide solution and a 1.0 molar silver nitrate solution were added at a constant flow rate over 2 minutes using a double jet addition method. A controlled pBr=0.85 was applied during this addition (consuming 1.75% of the total silver usage). After a 30 second hold, the emulsion's pBr at 65°C was adjusted to 1.22 (6.42% of total silver usage) by adding a 2.0 molar silver nitrate solution at a constant flow rate over 7.33 minutes. ). Then under controlled pBr (at 65°C) 2.29
26 molar potassium bromide solution and 2.0 molar sodium nitrate solution at accelerated flow rates (5.6x from start to finish) by double jet addition method.
added over a period of minutes (total amount of silver used)
(consumed 37.6%). The pBr at 65°C was then reduced to ~ by adding a 2.0 molar silver nitrate solution to the emulsion at a constant flow rate over 6.25 minutes.
Adjusted to 2.32 (consuming 6.85% of total silver usage). pBr = 2.29 molar potassium bromide solution and 2.0 molar silver nitrate solution controlled by double jet addition method applying constant flow rate
2.32 (at 65°C) over 54.1 minutes (consuming 47.4% of total silver usage). A total of about 9.13 moles of silver was used to prepare this emulsion. After precipitation, the emulsion was cooled to 40°C and 1.65 phthalated gelatin (15.3% by weight)
The solution was added and the emulsion was washed twice by the coagulation method described in U.S. Pat. No. 2,614,929 to Yutsui and Ratsel. Then 1.55
bone gelatin (13.3% by weight) solution, and the pH of the emulsion at 40 °C was 5.5, and the pAg
was adjusted to 8.3. The resulting tabular grain AgBr emulsion had an average grain diameter of 1.34 μm, an average thickness of 0.12 μm, and an average aspect ratio of 11.2:1. Addition of B AgBr shell 2.5 to 1.7 in a well-stirred 0.4 molar aqueous potassium nitrate solution containing 1479 g (1.5 mol) of the core emulsion.
A molar potassium bromide solution and a 1.5 molar silver nitrate solution were added at constant flow rates over a period of 135 minutes using the double jet addition method. Upon this addition, the controlled pAg = 8.2 (at 65°C)
(consumed 5.06 moles of silver). After precipitation, the emulsion was cooled to 40°C, a 1.0 phthalated gelatin (19.0% by weight) solution was added, and U.S. Pat.
The emulsion was washed three times using the coagulation method described in the above issue. A 1.0 bone gelatin (14.5% by weight) solution was then added and the pH of the emulsion at 40°C was adjusted to 5.5 and pAg to 8.3. The resulting tabular grain AgBr emulsion had a tabular grain diameter of 2.19 μm, an average thickness of 0.27 μm, and an average aspect ratio of 8.1:1. Also,
More than 80% of the projected area was provided by tabular grains. Emulsion 23B Soluble iodide (0.5 mol %) locally dominant substance 40.0 g (0.04 mol) of host emulsion 23A was added at 40°C.
0.5 mole % iodide was added by introducing a 0.04 mole potassium iodide solution at a constant flow rate over 10 minutes. The emulsion was centrifuged and resuspended in 18 x 10 ^-2 molar sodium chloride solution to a total volume of 40.0 g. Then 2.4 mol%
AgCl in host grain emulsion, pAg at 40°C
Precipitation was carried out by double jet addition of 0.55 M NaCl and 0.50 M AgNO ₃ solution at constant flow rate over 3.9 minutes while holding the pH at 7.5. Most of the epitaxially grown AgCl is exclusively
It was present at the corners of the tabular grains. Emulsion 23C Spectral sensitizing locally controlled substance 40.0g (0.04mol) of Emulsion 23A contains 0.10mol of
Add _AgNO3 solution and its pAg at 40 °C is 7.2
It was adjusted to Then 1.0 ml of 0.61 molar NaCl solution was added. This emulsion was mixed with 0.84 mmol/Agl mol of anhydro-5,5',6,6'-tetrachloro-
1,1'-diethyl-3,3'-di(3-sulfobutyl)benzimidazolocarbocyanine hydroxide was added and held at 40°C for 16 minutes. 2.44 mol % AgCl was then added into the host grain emulsion by double jet addition of 0.55 mol NaCl and 0.50 mol AgNO ₃ solution at constant flow over 3.9 min while maintaining the pAg at 7.5 at 40°C. and allowed to precipitate. Epitaxially grown AgCl was formed at the corners and along the edges of the AgBr tabular grains. Emulsion 23D (Control) No Local Dominants Deposition by epitaxial growth was repeated in the absence of both iodide and spectral sensitizing dye.
AgCl was deposited randomly over the entire surface of the host tabular grains. Example 24 In this example, selective orientation of silver salt epitaxy at staggered edge sites may be achieved using high aspect ratio tabular grains of the type disclosed in the Maskasky reference cited above. This will be explained. According to such a host tabular grain, a dodecagonal projection plane, i.e., a set of crystal planes [this is (111)
It is formed from 6 edges that exist on the crystal plane [which is considered to be a (110) crystal plane] and 6 edges that exist on a second set of crystal planes that alternate with these [this is considered to be a (110) crystal plane]. A projected surface is given. Emulsion 24A Tabular host grains with dodecagonal projection surface Poly(3-thiopentyl methacrylate co-coated)
Acrylic acid-co-2-methacryloyloxyethyl-1-sulfonic acid, sodium salt) (polymer
0.625%, molar ratio 1:2:7), adenine (0.021
A 3.0 aqueous solution containing sodium bromide (0.0126 mol) and calcium chloride (0.50 mol) was prepared at 55° C. and pH 2.6. An aqueous solution of calcium chloride (2.0 moles) and silver nitrate (2.0 moles) was added at a constant flow rate over a period of 2 minutes using the double jet addition method (consuming 3.98% of the total amount of silver used). The halide and silver salt solutions described above were then added using accelerated flow rates (2.3x from start to finish) for an additional 15 minutes (consuming 49.7% of the total silver usage). The halide and silver salt solution described above was then added at a constant flow rate over 10 minutes (consuming 46.4% of the total amount of silver used).
The PH value was maintained at ~2.6 throughout. A total of 2.26 moles of silver was used to prepare this emulsion. obtained
The tabular grains contained in the AaClBr (99.6:0.4) emulsion have dodecagonal projection surfaces, an average grain size of 3 μm, an average thickness of 0.25 μm, an aspect ratio of 12:1, and Over 85% was contributed by tabular grains. Preferential deposition of AgBr on the tabular grains of Emulsion 24B AgClBr Emulsion 2615 g of unwashed tabular grain AgClBr Emulsion 24A
An aqueous sodium bromide solution (0.128 mol) was added to (1.13 mol) at a constant flow rate by a single jet addition method (at 55°C for 5 minutes). Approximately 3.0 mole percent bromide was added. (111) of tabular silver halide grains
Silver bromide was preferentially deposited on the edges. Emulsion 24B was cooled to 20° C., diluted to about 14.0° C. in distilled water, stirred, and allowed to settle.
Decant the supernatant and add 330 g of the emulsion to 10
% bone gelatin in aqueous solution, and at 40 °C.
The pH was adjusted to 5.5 and pAg to 7.5. Emulsion 24B was mixed with 0.5 mmol/Ag 1 mol of anhydro-5-chloro-9-ethyl-5'-phenyl-3'-
(3-sulfobutyl)-3-(3-sulfopropyl)
Sensitized with oxacarbocyanine hydroxide and triethylamine salt. Next, this emulsion was added to 10mg/
Ag1 mole sodium thiosulfate 5H ₂ O, 1600
mg/Agmol sodium thiocyanate and 5
Chemically sensitized with sodium tetrachloroaurate at mg/mol Ag and held at 55°C for 5 minutes. Emulsion 24C A portion of AgBr emulsion 24A randomly deposited on the tabular grains of AaClBr emulsion was washed in a manner similar to that described for emulsion 24B above. Then, the washed emulsion was mixed with 0.5 mmol/Ag1 mol anhydro-5-chloro-9-ethyl-5'-phenyl-3'-(3-sulfobutyl)-3-(3-sulfopropyl)oxacarbocyanine hydroxide, triethylamine. Spectrally sensitized with salt. To this emulsion was then quickly added a sufficient amount of sodium bromide solution to give it 3 mole percent bromide (based on the moles of halide present in Emulsion 24A). This emulsion was then chemically sensitized according to the method described for Emulsion 24B. Electron micrographs of this emulsion revealed that silver bromide was deposited randomly on the surface of the grains. Emulsions 24B and 24C were coated on a cellulose triacetate support at a coverage of 2.15 g/m ² silver and 5.38 g/m ² gelatin. The resulting coating was exposed to a 600 W 5500 tungsten light source for 1/50 second through a continuous density wedge from 0 to 4.0. These coatings are N
-Methyl-p-aminophenol sulfate (Elon-ascorbic acid surface developer at 20°C)
The treatment was carried out for 10 minutes. From the sensitomere measurement results, it was found that the emulsion containing bromide was epitaxially grown on a {111} silver halide edge.
25B was found to be approximately 0.25 logE more sensitive than the control emulsion 24C (having silver bromide randomly deposited on the silver halide host tabular grains). In the case of emulsion 24B, relatively low (0.1 mol%)
Additional photographic sensitivity could be obtained when chemical and spectral sensitization was performed in the presence of concentrations of soluble iodide. Two additional emulsions similar to Emulsion 24B were prepared. These emulsions contained 0.6 mmol/Ag1 mol of spectral sensitizer, 7.5 mg/Ag1 mol of sodium thiosulfate/5H ₂ O, and 1600 mg/Ag1 spectral sensitizer.
Mol Sodium Thiocyanate and 3.5mg/Ag1
molar of potassium tetrachloroaurate and a hold time of 5 minutes at 65°C was used. In addition, 0.1 mol % of sodium iodide was added to one of these two emulsions before spectral sensitization.
These emulsions were evaluated for photographic speed as described above. The coating containing the iodide treated emulsion had a higher sensitivity by 0.38 logE when it was compared to that of the non-iodide treated emulsion. Example 25 This example illustrates that emulsions according to the present invention can exhibit higher covering power and faster fixing speeds than comparable emulsions containing nontabular host grains. Emulsion 25A Nontabular silver bromide host emulsion This emulsion was prepared by the conventional double jet precipitation method.
Prepared at PH=4.5 and pAg=5.1 (79°C). The formation of precipitates is described in European Patent Application No. 0019917 (1980
It was conducted in the same manner as disclosed in (published on November 10, 2017). The molar ratio of bromide to iodide was 77:23, as determined by X-ray diffraction. Furthermore, it was determined by this X-ray diffraction that the iodide was uniformly distributed. The particles were octahedral with an average diameter of 1.75 microns and an average particle volume of 2.5 cubic microns. Emulsion 25B Epitaxial growth of AgCl on nontabular emulsion 25A Silver chloride in an amount of 2.5 mol %, based on the total amount of halides, was added to host 8 of emulsion 25A according to the following procedure.
Epitaxially grown on hedral grains: 0.075
A molar amount of emulsion 25A was placed in a reaction vessel and distilled water was added to give a final weight of 50.0 g. 1.25ml
A 0.735M NaCl solution was added. 2.5 mol% AgCl was then added to this emulsion by double-jet addition of a 0.55 molar NaCl solution and a 0.5 molar AgNO ₃ solution at a constant flow over 5.5 minutes at 40°C and a controlled pAg = 7.5. and allowed to precipitate. Epitaxial growth occurred primarily at the corners of the host grains. Emulsion 25C Tabular Grain Silver Bromoiodide Host Emulsion A high aspect ratio tabular grain silver bromoiodide emulsion was selected based on an average grain volume of 2.6 cubic microns. This emulsion was substantially the same as Emulsion 25A. It was determined by X-ray diffraction that the molar ratio of bromide to iodide was 80:20 and that the iodide distribution was uniform. This emulsion has an average tabular grain diameter of 4.0 microns, an average tabular grain thickness of 0.21 microns, and an average aspect ratio of 19:1.
The average particle volume was 2.6 cubic microns.
More than 90% of the total projected area of the silver halide grains was occupied by tabular grains. Emulsion 25D Epitaxial Growth of AgCl on the Tabular Grains of Emulsion 25C The same silver chloride deposition process as described in the preparation of Emulsion 25B was used. However, in the case of this emulsion, emulsion 25C was first placed in the reaction vessel instead of emulsion 25A. Deposition by epitaxial growth is
It was mainly observed at the corners and edges of the host tabular grains. Control emulsion 25B was coated on a polyester film support at a coverage of 2.83 g/m ² silver and 10 g/m ² gelatin. This coating film was passed through a step tablet with a density of 0 to 6.0 (0.30 density step) to 600W3000.
Exposure to a tungsten light source for 1/2 second and processing in N-methyl-p-aminophenol sulfate (Elon)-hydroquinone developer for 20 minutes at 20°C. Emulsion 25D was coated at a coverage of 2.89 g/m ² silver and 10 g/m ² gelatin and exposed and processed in the same manner as Emulsion 25B. Emulsion 25D exhibited superior covering power compared to the control nontabular emulsion 25B at similar emulsion grain volumes and similar silver coverage. emulsion
25D exhibited a minimum density of 0.16 and a maximum density of 1.25 compared to the control emulsion 25B's minimum density of 0.10 and maximum density of 0.54. Based on X-ray fluorescence analysis, the control emulsion coating had a D _nax of 97.2%.
of silver was developed, and in the case of tabular grain emulsion coatings, 100% of the silver was developed. Separate untreated portions of Emulsion 25B and Emulsion 25D coatings were washed in a sodium thiosulfate fixing bath (Kodak
F-5) at 20° C. for various times and then washed for 30 minutes. Silver remaining in the coating film was analyzed by X-ray fluorescence. As shown in Table XI below, the fixing rate of the tabular grain epitaxially grown emulsion coatings was greater than that of the octahedral grain epitaxially grown emulsion coatings.

[Table] (5) Effects and Advantages of the Invention The tabular silver halide emulsion of the present invention has enhanced sensitization sites because the sensitization sites are located in relation to the tabular grains and preferably in relation to each other. It has sensitivity. The present invention represents a significant improvement over the prior art in this field. In one form of the invention, art-recognized techniques for chemical sensitization, i.e. reduction, gold (noble metal) and/or
Very high sensitivities can be achieved even with tabular grain emulsions according to the invention that have not been sensitized with sulfur (intermediate chalcogen) sensitizers. The present invention can also provide a number of additional advantages that are directly attributable to the presence of epitaxially deposited silver salts. These advantages are described in detail below. The emulsions of this invention also offer the advantage of unique photographic response over conventional non-tabular emulsions which carry epitaxially deposited salts on the grain surfaces. By using emulsions according to the invention, especially emulsions with large average grain diameters, the sharpness of photographic images can be improved. Emulsions of the invention, when spectrally sensitized outside the blue region of the spectrum, exhibit greater sensitivity separation in the blue region of the spectrum compared to the region of the spectrum to which they are spectrally sensitized. . Negative blue sensitized emulsions containing tabular silver bromide and silver bromoiodide host grains according to the invention are much less sensitive to blue light than to negative blue light, and also have, for example, 5500 When exposed to neutral light such as daylight, filter protection is unnecessary to produce an acceptable negative blue exposure record. When a blue spectral sensitizer was used, a very large increase in blue sensitivity could be achieved compared to the original blue sensitivity exhibited by the emulsions of the present invention. The emulsions according to the invention can be used in any photographic application, for example in radiographic elements coated on both major sides of a radiolucent support to control crossover. Comparing a radiographic element containing an emulsion according to the invention with a similar radiographic element containing a conventional emulsion shows that reduced crossover can be achieved with the emulsion according to the invention. I understand. Achieving comparable crossover values when using reduced silver coverage and/or realizing an improved speed-granularity relationship when using emulsions of the present invention, as the case may be. Can be done. Emulsions according to the invention can also be used in image transfer film units. The image transfer film unit is capable of forming a visible image with a short elapsed time after the start of processing. A transfer image with higher contrast can be realized even with a shorter development time. Furthermore, by using such an image transfer film unit, it is possible to form images with improved sharpness. The emulsions of the present invention provide reduced silver coverage, more efficient use of dye imaging materials in the image transfer film unit, more advantageous layer configurations, elimination or reduction of yellow filter material, and generally reduced temperature dependence of the image. Allow for decline.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between granularity and sensitivity, Figure 4 is a conceptual diagram of an apparatus for quantitatively measuring light scattering, and Figures 2, 3, and 5 are graphs showing the relationship between granularity and sensitivity.
Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10
11a, 11b, 12, 13
Fig. 14, Fig. 15, Fig. 16, Fig. 17,
Figure 18, Figure 19, Figure 20, Figure 21, Figure 2
Figures 2, 23, 24, 25, and 26
Each figure is an electron micrograph of an emulsion sample. In FIG. 1, 1, 2, 3, 4, 5, 6, 7 and 8 each indicate a silver halide emulsion.

Claims (1)

[Scope of Claims] 1. A tabular grain silver halide emulsion comprising a dispersion medium and silver halide grains, wherein at least 50% of the total projected area of the silver halide grains has a thickness of less than 0.5 micrometer. is dominated by tabular grain silver halide grains having a diameter of at least 0.6 micrometers and an average aspect ratio greater than 8:1, said tabular silver halide grains having opposing parallel {111} main grains. A tabular grain halogen having crystal planes, and a silver salt having a composition different from the silver halide forming the tabular grain is arranged at the edge of the tabular grain. Silver emulsion. 2. The tabular grain silver halide emulsion according to claim 1, wherein the silver salt is arranged at the corner of the tabular grain. 3. The halogenated tabular grain according to claim 1 or 2, wherein the tabular grain consists of silver bromide or silver bromoiodide, and the silver salt consists of silver chloride or silver thiocyanate. silver emulsion. 4. The tabular grain silver halide emulsion according to claim 1, 2 or 3, wherein the silver salt contains a sensitivity improver. 5. At least 50% of the total projected area of the particles is
Thickness less than 0.3 micrometer, diameter minimum 0.6
Tabular grains according to claim 1, 2, 3 or 4, dominated by tabular grains of micrometers and having an average aspect ratio greater than 8:1. Grain silver halide emulsion. 6. A tabular grain silver halide emulsion comprising a dispersion medium and silver halide grains, wherein at least 50% of the total projected area of the silver halide grains have a thickness of less than 0.5 micrometer and a diameter of at least 0.6 micrometer. m, and is dominated by tabular silver halide grains having an average aspect ratio of greater than 8:1, and the tabular silver halide grains have opposing parallel {111} principal crystal faces. , and a tabular grain silver halide emulsion, characterized in that a silver salt containing a sensitivity improver is arranged at the edges of the tabular grains. 7. At least 50% of the total projected area of the particles is
Thickness less than 0.3 micrometers, diameter at least 0.6 micrometers, and average aspect ratio 8:
7. A tabular grain silver halide emulsion according to claim 6, which is dominated by tabular grains of greater than 1. 8. A tabular grain silver halide emulsion comprising a dispersion medium and bromoiodide grains, wherein at least 50 of the total projected area of the silver bromoiodide grains
% is dominated by tabular silver bromoiodide grains having a thickness of less than 0.5 micrometers, a diameter of at least 0.6 micrometers, and an average aspect ratio greater than 8:1; Parallel {111} in which silver oxide grains face each other
the tabular silver bromoiodide grains contain less than 5 mol % iodide in their central region and at least 8 mol % iodide in a laterally extending annular region surrounding said central region; % of iodide, and a silver salt having a composition different from the silver bromoiodide forming the central region forms the opposing parallel main grains formed by the central region of the tabular grain. A tabular grain silver halide emulsion characterized in that it is arranged on a portion of a crystal plane and its arrangement is restricted to that portion. 9. At least 50% of the total projected area of the particles is
Thickness less than 0.3 micrometer, diameter minimum 0.6
9. A tabular grain silver halide emulsion according to claim 8, which is dominated by tabular grains of micrometers and having an average aspect ratio greater than 8:1.